Cam Selection (Non-Roller)

[Shaun]

Grumpy,

Sorry if this is lengthy, I am just trying to be thorough. Most guys seem to ask blanket questions without providing many critical details. Hopefully you can help me out here with my 82’ square body. I have a late 80’s C/K 454 truck block. With the peanut port heads (113cc?) I believe compression is in the high 7’s. I have 048’s on it right now (122cc?). First question is, what do you think my compression is with the 049’s? Or better yet do you know what pistons are in the truck block so I can do my own math?

Camshaft wise, I have no clue what is in it, the guy before me may have cammed it, but my gut instinct is that it is the stocker (somewhere around 193-204 deg's duration @.050 and a lift of .398-.430). Second question, what do you think would be the ideal idle – 5200 rpm or so cam selection? With the ultra-low compression, I have no clue where to go with duration, or even LSA. I prefer as narrow LSA as possible for idle lope- I am currently running a Quadra Jet / mechanical ZZ4 distributor- 14/34/50ish canned with light advance springs, so computer compatibility is not a problem. Carter high volume mechanical fuel pump, Edelbrock Performer 2-O intake, 74’ LT4 exhaust manifolds, true 2.5” duals through Flowmaster 40’s turned out.

I would love to just toss some pistons in it, be in the range of 9:3:1 – 9:5:1, and utilize the million tried and tested combos out there for me to copy and paste, but funds just are not there quite yet to tear the motor apart (unless if you know someone selling budget cast pre balanced Gen IV rotating assemblies (stock external or internal). I just want to get this one running stronger as is and then down the road do the short block up 496 style.

I have ran it for about 15 years. It is decent, like any big block. I always say a sick or aged big block is like a healthy, moderate 350 small block. It seems like it should have stronger torque off the line than it does. It feels hills, and a low RPM big block not towing shouldn’t feel hills in my opinion. It could be because stuff got mismatched.

Initially I had an alright setup (power wise, not strength wise)… I yanked the 350 out and the 454 actually moved pretty good and even chirped first gear hard. Hard enough that I enjoyed it, got addicted, kept doing it, and blew the TH350 (shocker- but I had to . It also had a GM Corporate 10 bolt with 342’s-so a very light drivetrain. I replaced the TH350 with a built T400 I bought from a Buddy whose wealthy father funded his square body 572 crate build that he basically ruined before it even got to be broken in. Good news, trans was done up, billet shafts and all yada yada. Bad news, he had a Coen with a 2300-2600 stall (I misplaced the stats but I can dig them up if you want). I didn’t have the money at the time to get creative with torque converter matching, so I just through it in, along with a NP205 I sourced and had been sitting on (it had a NP208), and also a 14 bolt SF (with 342’s). I have always ran 33x12.5x15 BFG’s on it since day one, or my backup set of 31x10.5’s.

My conclusion- no kidding I need gear- but it ran a lot harder before the drivetrain changes (it is a big block and I am talking street here, not crawling), which granted adds a lot of weight. But it lost so much of the line torque that I can’t help but wonder if the high stall speed set up for the revving higher compression 572 is killing my off idle torque. Of course I have no clue what my current torque curve even looks like (flat, strong low then falls off quick?).

Further making me think it is the torque converter (and granted the first gear loss of the TH400) is the fact that I put a Dana 60 up front about two years ago and I had no loss in power- and that sucker is a heavy SOB compared to the ½ ton it replaced.

So, the Dana 60 has 456’s (which I wanted). I will either 456/Detroit the 14BSF, or go ahead and just get a 14BFF with the 456’s already there, do it up like my front so I can still run my aluminum 15” slots that I have ran since the mid-nineties. Either way will cost about the same, only I will have the FF (the SF is kind of hard to shim and crush, and there is just not the plethora of cheat sheets out there like the FF with its “fine tracking knob”). I have read that small blocks like the SF up to about a 37” tire. I plan to run a 37-40” tire with my big block that will be done up healthy one day so I better have the FF’s insurance factor.

The only other change will be swapping in a 4l80e. That and a lift will come next tax season. Sorry, I live on a blue collar income, family of five- try to spoil the kids a little, and do things for myself on a tax season basis- I call it adult Christmas. I have several other vehicles/toys, so each one goes through its come and go periods of trying getting my love. This is my only big block, and I just don’t know them blind folded like my OG small blocks and LS’s variants. I have had fun with it over the years, but my other stuff is getting caught up and it is time to refine this one.

So, to summarize my TMI rant, super low compression 454, 049 heads, turbo 400 with 2300 -2600 stall (will be 4l80e by next year), NP205, 342 gears (456 gears SOON)- please help me find a good strong cam that will make this thing jump off the line hard, and should I stick with the stall for now and just get nit-picky when I get the 496 short block properly prepped for the 049 heads, or do you think that I should put a budget unit in now. I feel like I should be around 1200-1500 stall. I am not revving it and probably not going to be going crazy with duration based on my wacky mis-matched compression.

If I had to guess, I would say .440/.450 – .490/.500 range on the lift, @.50- 212° Intake / 218° for the duration, and 111 or narrower LSA (not just sound, I want the instantaneous pedal leap also). What do you think Grumpy? And I don’t tow a lot, but have a couple of 80’s boats around 3500lbs that I tow to the lake here and there and will tug people out of the mud/snow from time to time. I really like torque, I am a believer of the saying “torque wins races, HP sells motors”. No rock climbing, so stiff suspension. Pretty much a street truck that can take a dip in a bog from time to time. Thanks for any considerations and taking the time to read all of this.

 

[Maniacmechanic1]

Your Not going to keep up or do anything compared to that 572 Ci BBC Unless You Build a Full Blown Drag Race Engine.

If You had Tire chirping power before and it's gone now there is a reason for it.
Check your ignition timing.
Initial and total advance.
With the timing light look at the balancer mark and rev the engine up.
If the timing mark moves dances all around erratic your looking at a stretched worn out timing chain.

Pull out all 8 spark plugs.
Do a compression test.
Record all.
With a low compression 7.0 -8.0 :1 Engine its a good 87 octane burner.
Important for deep trail rides.
None will have 93 -110 octane gasoline if you run out.
You should have 160-165 psi cranking compression.

 

[Maniacmechanic1]

A 4 wheel Drive truck used in real life should be able to run on 87 octane gasoline WOT Non stop.
No fancy tricks.
It's a Doomsday Vehicle.

You can build for 93 pump gas or 110 race fuel.
Be worthless on deep trails 20-50 miles deep.
93 pump gas engines done here on Grumpys 99.9 % of the time.

I know 87 octane to 120 race fuel engines.

 

[Grumpy]

swapping to the 049 heads won,t boost effective compression
353049.....73-84...oval...OPEN...454, 122cc chamber, 255/119cc ports


theres several 97cc-102cc closed chamber BBC heads available,
that would result in higher compression,
but if your going to swap heads theres better options.

lots of web sites would have a dozen guys suggesting cams,
but I've always suggested anyone contemplating changes to start from a verified and well understood basic engine,
its silly in my opinion to start throwing parts at any engine until your 100% sure,
its already in decent condition and your not simply wasting time and money on new parts that will only cost you even more time and cash.
,until you correct the basic problems with the stock engines function.
step one would be to, verify exactly what your dealing with,
do a compression & LEAK DOWN test,

and to accurately measure the current cam lobe/valve lift,

http://www.igagingstore.com/MAGNETIC-BASE-FLEXIBLE-FLEX-ARM-001-DIAL-INDICAT-p/203957.htm

dial indicator with stand

verify the ignition timing advance curve
and post clear, detailed color pictures of your spark plugs, labled as to cylinder location.

what does a vacuum gauge show?
whats your oil pressure at idle?
whats the exhaust back-pressure at peak rpms?
whats your fuel pressure and does it change with rpm changes?
do you know exactly how to properly adjust the valve train?

http://www.earlycuda.org/tech/vacuum2.htm

http://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html
I got mine at harbor freight for about $19, and it works fine, sears sells the same gauge for a few dollars more and similar gauges are available at advance auto
READ THRU THE LINKS
http://www.sears.com/u-s-general-fuel-p ... 5887561009

http://www.secondchancegarage.com/public/186.cfm

http://www.sears.com/shc/s/p_10153_1260 ... 921x00003j

http://www.earlycuda.org/tech/vacuum2.htm

http://www.international-auto.com/fiat- ... gauges.cfm

you can,t guess you need to deal in verified facts.
currently your don,t really know what your dealing with,
its physical operational condition or if you have worn cam lobes,leaking valves or worn rings etc
. it won,t do you much good too consider swapping cams,
until you've verified the basic engines operational condition tuning and compression, timing etc. is OK.
let us know
What you find,
before we go further


http://garage.grumpysperformance.co...-running-up-to-expectations.14757/#post-81014

http://garage.grumpysperformance.com/index.php?threads/verifying-your-real-advance-curve.4683/

http://garage.grumpysperformance.co...-articles-you-might-want-too-look-over.14682/

http://garage.grumpysperformance.co...ng-carb-with-just-vac-gauge.14932/#post-84207

https://www.harborfreight.com/catalogsearch/result/index/?dir=asc&order=EAScore,f,EAFeatured+Weight,f,Sale+Rank,f&q=94190

 

[Maniacmechanic1]

The Quadrajet carburetor is worth looking at also.
There are tiny air bleeds in the upper air horn that often plug up from dirt getting through the air cleaner.
Happens more often on 4x4 trucks used off road.
Also Idle down emulsion tubes that can plug up that effect the entire air fuel ratio curve idle to WOT.
Accessed by removing the upper air horn.
If the engine has been running poorly then it has seen engine backfire likley.
The Power piston is blow out proof in a Quadrajet. They often stick full down Lean or full up Rich position from carbon from engine backfires.

 

[Maniacmechanic1]

swapping to the 049 heads won,t boost effective compression
353049.....73-84...oval...OPEN...454, 122cc chamber, 255/119cc ports


theres several 97cc-102cc closed chamber BBC heads available,
that would result in higher compression,
but if your going to swap heads theres better options.

lots of web sites would have a dozen guys suggesting cams,
but I've always suggested anyone contemplating changes to start from a verified and well understood basic engine,
its silly in my opinion to start throwing parts at any engine until your 100% sure,
its already in decent condition and your not simply wasting time and money on new parts that will only cost you even more time and cash.
,until you correct the basic problems with the stock engines function.
step one would be to, verify exactly what your dealing with,
do a compression & LEAK DOWN test,

and to accurately measure the current cam lobe/valve lift,

http://www.igagingstore.com/MAGNETIC-BASE-FLEXIBLE-FLEX-ARM-001-DIAL-INDICAT-p/203957.htm

dial indicator with stand

verify the ignition timing advance curve
and post clear, detailed color pictures of your spark plugs, labled as to cylinder location.

what does a vacuum gauge show?
whats your oil pressure at idle?
whats the exhaust back-pressure at peak rpms?
whats your fuel pressure and does it change with rpm changes?
do you know exactly how to properly adjust the valve train?

http://www.earlycuda.org/tech/vacuum2.htm

http://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html
I got mine at harbor freight for about $19, and it works fine, sears sells the same gauge for a few dollars more and similar gauges are available at advance auto
READ THRU THE LINKS
http://www.sears.com/u-s-general-fuel-p ... 5887561009

http://www.secondchancegarage.com/public/186.cfm

http://www.sears.com/shc/s/p_10153_1260 ... 921x00003j

http://www.earlycuda.org/tech/vacuum2.htm

http://www.international-auto.com/fiat- ... gauges.cfm

you can,t guess you need to deal in verified facts.
currently your don,t really know what your dealing with,
its physical operational condition or if you have worn cam lobes,leaking valves or worn rings etc
. it won,t do you much good too consider swapping cams,
until you've verified the basic engines operational condition tuning and compression, timing etc. is OK.
let us know What you find,
before we go further


http://garage.grumpysperformance.co...-running-up-to-expectations.14757/#post-81014

http://garage.grumpysperformance.com/index.php?threads/verifying-your-real-advance-curve.4683/

http://garage.grumpysperformance.co...ng-carb-with-just-vac-gauge.14932/#post-84207

https://www.harborfreight.com/catalogsearch/result/index/?dir=asc&order=EAScore,f,EAFeatured+Weight,f,Sale+Rank,f&q=94190

Leakdown is often Terrible on High mileage engines Grumpy.
Not uncommon to see 20-40 % Leakdown rates !
Not the 0-1 % wanted on a Race Engine New.
Some use 3-4 % Leakdown.

Like the Cranking compression test 1st myself.

 

[Grumpy]

theres little sense in "BEATING A DEAD HORSE"
or throwing cash, and new parts into an engine with its basic operational requirements not being reached,
yeah, we would all like to throw $150 dollars into some engine project and see an instant 40-50 hp,
the problem is frequently not a lack of the newer performance component, but the fact the basic tuning and,
operational conditions in the existing engine are not even allowing the stock engine to operate to its full potential.
simple stuff like a clogged catalytic converter or a couple worn cam lobes or the wrong ignition advance, a partly clogged fuel filter a restrictive air filter,
can cause major power loss,
but as it generally comes on very slowly over months its not easy to see its effect.

 

[Maniacmechanic1]

theres little sense in "BEATING A DEAD HORSE"
or throwing cash, and new parts into an engine with its basic operational requirements not being reached,
yeah, we would all like to throw $150 dollars into some engine project and see an instant 40-50 hp,
the problem is frequently not a lack of the newer performance component, but the fact the basic tuning and,
operational conditions in the existing engine are not even allowing the stock engine to operate to its full potential.
simple stuff like a clogged catalytic converter or a couple worn cam lobes or the wrong ignition advance, a partly clogged fuel filter a restrictive air filter,
can cause major power loss,
but as it generally comes on very slowly over months its not easy to see its effect.

Its a Big Chevy. They are tough.
Bad Cam Lobe it needs to be pulled. Rebuilt.

 

[Shaun]

Your Not going to keep up or do anything compared to that 572 Ci BBC Unless You Build a Full Blown Drag Race Engine.

If You had Tire chirping power before and it's gone now there is a reason for it.
Check your ignition timing.
Initial and total advance.
With the timing light look at the balancer mark and rev the engine up.
If the timing mark moves dances all around erratic your looking at a stretched worn out timing chain.

Pull out all 8 spark plugs.
Do a compression test.
Record all.
With a low compression 7.0 -8.0 :1 Engine its a good 87 octane burner.
Important for deep trail rides.
None will have 93 -110 octane gasoline if you run out.
You should have 160-165 psi cranking compression.

“Your Not going to keep up or do anything compared to that 572 Ci BBC Unless You Build a Full Blown Drag Race Engine.”

-I think a full blown drag engine is a little excessive in comparison to a crate 572. Most GM crate engines ship with relatively mild cams from the factory. With a forged crank, ARP bolts on the rotating assembly, and SS valves I think a cammed 454 would give a stock 572 a good run for its money. Would it be as durable, probably not, would it be able to hang in there if the 572 was cammed, probably not. I always thought of a 572 as a wealthy man’s plug and play cost for car club admission. Most serious builders would not spend that much money for what the 572 is. They would buy a Merlin block, Scat or Callies crank, ect ec.



“If you had Tire chirping power before and it's gone now there is a reason for it.”

-I think the reason it is loss of drivetrain. I have added a lot of weight to the truck. And suburban’s are already heavy to begin with. I have an S10 with a tweaked 3.4- same thing. Swapped out the Th250/7.5 10 bolt for a 700R4/Ford 8.8. The light weight 10 bolt (I can easily do 50 plus full range arm curls with it) had 294’s, I swapped in a similar 10 bolt but with 411’s. Much power gain of the line. The 8.8 with 373’s was noticeably slower than both 10 bolts, though in all fairness the trans swap was done when the 8.8 was done. Lower first gear ratio on a not so torquey (in V8 comparing) 60 degree V6, quite a bit of rotating weight added. The point I am making is that drivetrain weight plays a huge part in final power levels. If you don’t concur, please explain to me the difference between flexplate rated power and rear wheel rated power on a dyno. I was not really looking for an explanation as I already had one, rather I was curious about the stall speed. A peanut cammed low compression engine with tall gearing has no business playing around with a higher stall speed- you following??



“Check your ignition timing.”

Why??? I already know what it is… and it was the same prior to the drivetrain modifications. I will definitely play around with it once I throw a different cam in. Not there yet though, hence why I posted.



“Initial and total advance.”

-I am currently running “” 14/34/50ish canned with light advance springs. The fact that I said ZZ4 dist means I have 20 degrees of centrifugal advance, so really my timing is 14 initial/20 centrifugal/20 pulled in by the can hooked to manifold vacuum. This is where it has been all along, before and after the driveline modifications. The can does not apply since anytime I am hitting the gas the can is bypassed, and the can I still play around with from time to time. So for the off line power, base of 14 and centrifugal of 20 gives me a total of 34. The springs are light giving me full advance by 2200. It took some trial and error to figure out where the 454 was comfortable. Possibly you have timed a 6:5:1 – 7:5:1 454 and have time tested results you could offer? The engine is running great. That is really not the issue here. For reference, I can spank my brother in laws 2006 Ford diesel effortlessly. I never said it was slow, just that it slowed down after the drivetrain changes (which should be expected).


“With the timing light look at the balancer mark and rev the engine up.
If the timing mark moves dances all around erratic your looking at a stretched worn out timing chain.”

-Timing chain was replaced by me way back when I put the intake on. Chloes double roller. I have probably only put 3000 miles on the truck since. So same chain before and after drivetrain changes. Again, I am not asking for engine troubleshooting advice, but rather cam selection. No one on the internet has actually cammed an 86’ 454 with 049 heads and posted results that I have found. All the tech info I have found applies to more popular compression ratio ranges. This is not a vanilla 454 build, so the answer is not really “Googleable”. I have a lot of knowledge, a lot. I will probably be able to figure out something on my own. Grumpy is one of the few individuals I know of who has both more knowledge than me and has played with a lot more big block combos than me. I can’t be the first person to have 049’s on a late 80’s truck block…

“Pull out all 8 spark plugs.
Do a compression test.
Record all.

You should have 160-165 psi cranking compression.”

-My compression has not changed since I first got the engine and I check it every few years or so whenever I replace the plugs. Lowest cylinder is 160, highest is 175 (I have the exact readings written down at my shop 6 miles away from me, I could add them later). A total span of 15 is not ideal, but been consistent all along baseline wise. The engine itself runs great. Since I do not know what camshaft is currently in it, I would like to replace it “so I know” and give the old 454 one last hoo-rah in its present form before I send the short block off to the machine shop in a few years. Granted I could pull the cam and mic it, but if I am going to go through all of that trouble why not just replace it with the biggest and baddest (torque biased) I can within the engines parameters- you following? I last did the compression in October of 18’ when I had the manifolds of to cerekote them. I only get 8-10 miles per gallon (gear should help that), and do not use it as a daily driver, so really it doesn’t get used enough to really wear it out any further.

 

[Shaun]

A 4 wheel Drive truck used in real life should be able to run on 87 octane gasoline WOT Non stop.
No fancy tricks.
It's a Doomsday Vehicle.

You can build for 93 pump gas or 110 race fuel.
Be worthless on deep trails 20-50 miles deep.
93 pump gas engines done here on Grumpys 99.9 % of the time.

I know 87 octane to 120 race fuel engines.

“With a low compression 7.0 -8.0 :1 Engine its a good 87 octane burner.
Important for deep trail rides.
None will have 93 -110 octane gasoline if you run out.”

-I do like the ability to run 87 octane, hence why I will never re-build with super high compression. I even stay conservative at 34 degree total as I do not run a knock sensor. This truck is not competing, so balancing performance with durability and efficiency is what I am after. I am really not looking to talk about my future build at this time, I already know what I want to do with the engine down the road. Once it crosses into “vanilla” build territory the information floating around out there becomes rather abundant.

Now with all due respect, I am looking for advice on cam selection. Do you have an opinion on that, or just wish to up your post count by drifting of the topic path into an area where you feel verbally more comfortable?

 

[Shaun]

swapping to the 049 heads won,t boost effective compression
353049.....73-84...oval...OPEN...454, 122cc chamber, 255/119cc ports


theres several 97cc-102cc closed chamber BBC heads available,
that would result in higher compression,
but if your going to swap heads theres better options.

lots of web sites would have a dozen guys suggesting cams,
but I've always suggested anyone contemplating changes to start from a verified and well understood basic engine,
its silly in my opinion to start throwing parts at any engine until your 100% sure,
its already in decent condition and your not simply wasting time and money on new parts that will only cost you even more time and cash.
,until you correct the basic problems with the stock engines function.
step one would be to, verify exactly what your dealing with,
do a compression & LEAK DOWN test,

and to accurately measure the current cam lobe/valve lift,

http://www.igagingstore.com/MAGNETIC-BASE-FLEXIBLE-FLEX-ARM-001-DIAL-INDICAT-p/203957.htm

dial indicator with stand

verify the ignition timing advance curve
and post clear, detailed color pictures of your spark plugs, labled as to cylinder location.

what does a vacuum gauge show?
whats your oil pressure at idle?
whats the exhaust back-pressure at peak rpms?
whats your fuel pressure and does it change with rpm changes?
do you know exactly how to properly adjust the valve train?

http://www.earlycuda.org/tech/vacuum2.htm

http://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html
I got mine at harbor freight for about $19, and it works fine, sears sells the same gauge for a few dollars more and similar gauges are available at advance auto
READ THRU THE LINKS
http://www.sears.com/u-s-general-fuel-p ... 5887561009

http://www.secondchancegarage.com/public/186.cfm

http://www.sears.com/shc/s/p_10153_1260 ... 921x00003j

http://www.earlycuda.org/tech/vacuum2.htm

http://www.international-auto.com/fiat- ... gauges.cfm

you can,t guess you need to deal in verified facts.
currently your don,t really know what your dealing with,
its physical operational condition or if you have worn cam lobes,leaking valves or worn rings etc
. it won,t do you much good too consider swapping cams,
until you've verified the basic engines operational condition tuning and compression, timing etc. is OK.
let us know What you find,
before we go further


http://garage.grumpysperformance.co...-running-up-to-expectations.14757/#post-81014

http://garage.grumpysperformance.com/index.php?threads/verifying-your-real-advance-curve.4683/

http://garage.grumpysperformance.co...ng-carb-with-just-vac-gauge.14932/#post-84207

https://www.harborfreight.com/catalogsearch/result/index/?dir=asc&order=EAScore,f,EAFeatured+Weight,f,Sale+Rank,f&q=94190

Grumpy, thanks for the response. I think you misunderstood me. I already have 049 heads on the engine, as it has sat in the engine compartment running for over 15 years.



I know there are better head options out there, but for now I am just concerned about upgrading the cam for sh$ts and giggles. 049 heads will work GREAT when I rebuild the short block down the road. I am a fan of the “Keep your GM vehicle GM”, and for the most part try to do that. With that being said, having the highest flowing oval ports the GM ever offered on a heavy 1 tonned suburban is a good idea, in my opinion.



“I've always suggested anyone contemplating changes to start from a verified and well understood basic engine”

-That is why I am here. I do not currently have a verified and well understood basic engine. If I did, I would not have a need to ask cam questions, you know what I mean? I figured, if there was anyone who would possibly have a better understanding than me of the”non-vanil” build it would be you. I totally understand if you just say “I don’t know” what a good cam would be. That is where I am at and I have been around the block a few times.



Regardless of compression readings, there is an ideal cam out there for my situation. With the peanut cam, it likes the restricted ports of the peanut heads for scavenging effect.. So, with the 049’s, I am actually hurting power with the huge runners (kind of why Bowtie Vortec Heads come in small and large port). I know I can put a cam in that would increase lift without hurting the toque band, and since starting off with the peanut cam actually increase it throughout the RPM range quite effectively. My compression numbers are good, the engine runs healthy, I gave each cylinder 5 minutes and witnessed zero leak down. If you want to see the actual results for all eight cylinders I could dig them up for you. I don’t know why that would have anything to do with cam selection, but you may know something I don’t. The block has a rebuild tag of 1998, so it is not as old as it appears. It was used in a church van before I got it, so only used for picking up and driving local people home. Not super high on the mileage, though exact mileage unkown.

I could use the dial indicator to figure out some of my cam specs, but it would be more work to tear the heads off then it would be to just do a quick cam swap. Since I am going to re-build the small block in a year or two anyways, I really just want to focus on the cam right now. Or cams, I may do a few cam changes just to provide internet research for people out there who for whatever reason are not or cannot jump on the vanilla build bandwagon.

It is so easy for people to say “just change the pistons”. It is kind of like when people say “don’t build the 305, it will never be a runner, scrap it for a 350”. I have one of the fastest 305’s in the country right now sitting in a G-body. And it’s running a CCC quadrajet. I self programmed the bipolar PROM back in the 90’s when everyone said it could not be done (I hacked GM’s source code). My point, sure it is a lot easier to stick with verified and well understood basic engines… yet sometimes it is the challenge of playing with the odd ball non vanilla stuff that can be fun and different.

As far as vacuum, it is around 17hg, most peanut cams allow the engine to make great vacuum. I converted to a hydro-boost years ago, so don’t worry about factoring in camshaft vacuum issues as I do not have vacuum assist brakes. I just know that duration and compression are related. Trying to figure out a good starting point on cam swaps here.

So, engine is healthy, possibly I did not make that clear when talking about losing rear wheel power through added loss of drivetrain. I doubt most people have ever experience the drastic change I experienced as the TH350/NP208 combo was only offered in 1982.



Grumpy, do you have an educated guess on a good starting point for a cam swap, or are you sticking with I don’t know? I don’t know either, so don’t let it hurt your pride if you don’t know. That is why I am taking on this project. I am curious and there is no data out there on it.

 

[Shaun]

theres little sense in "BEATING A DEAD HORSE"
or throwing cash, and new parts into an engine with its basic operational requirements not being reached,
yeah, we would all like to throw $150 dollars into some engine project and see an instant 40-50 hp,
the problem is frequently not a lack of the newer performance component, but the fact the basic tuning and,
operational conditions in the existing engine are not even allowing the stock engine to operate to its full potential.
simple stuff like a clogged catalytic converter or a couple worn cam lobes or the wrong ignition advance, a partly clogged fuel filter a restrictive air filter,
can cause major power loss,
but as it generally comes on very slowly over months its not easy to see its effect.

Grumpy, I don’t think it is fair to call my engine a “dead horse”. It is very strong in the state it is in right now. It has a peanut cam, I guarantee you that I can throw a $150 camshaft in it and pickup 40-50 hp. Even small blocks with the peanut tbi and better heads cam see those type of gains.

I have raced and beat early turbo diesel’s- I assure you that basic operational requirements are being met.



“basic tuning and, operational conditions in the existing engine are not even allowing the stock engine to operate to its full potential.”

-Where are you getting that from? It is tuned pretty well for what it is, even dyno tuning it will not allow it to due much more than it is with low compression and the peanut cam. You lost me. I have been tuning quadrajets and HEI’s for 25 years. Most can’t say that. Most call quadrajets “quadrajunks” and ditch the HEI for Mallory or MSD systems. I have stuck the course with this stuff. I didn’t give up on the quadrajet and GM HEI, I stuck with it have mastered it.

I don’t have a converter for it to be clogged, cam lobes would show on the vacuum gauge and my idle would not be so perfect, to perfect, hence why I want the narrow LSA. Fuel filter is long element quadrajet that I replace every year. Air filter housing is the largest C/K offered, with a clean filter changed as needed. No K&N here, oil and dust clog up quick and the larger mesh of the K&N to offset the oil allows larger particulate matter in. Peanut cam low revving big blocks are not that air choked up anyways.

 

[Shaun]

Its a Big Chevy. They are tough.
Bad Cam Lobe it needs to be pulled. Rebuilt.

“It’s a Big Chevy. They are tough. Bad Cam Lobe it needs to be pulled. Rebuilt.” Exactly, big Chevy’s are tough. But a bad cam lobe does not necessarily mean it has to be rebuild- though the industry would like you to think so from a marketing point of view. It all depends on the compression after the failure, if the particulate from the lobe hurt the pistons or crank bearing enough to provide horrible compression results. BTW, my cam is not bad, my motor is not bad. I feel like everyone is digging to avoid simply saying nothing at all or I don’t know. I don’t know either, that is why I am going to experiment with cams on an oddball combination, a combination that is super cheap, actually makes decent power, and makes for a good foundation to build upon. How many guys have you known over your life you always I I am not going to do it until I can do it all right and perfect the first time? And what- unless if the guys become financially comfortable, they never end up actually having anything because not only did the fear keep them from having “something”, but it kept them from having a toy to play with that refined their mechanic skills. They end up wanting perfect and having to out-source all their money to have it. Meanwhile, a guy like me, at a young and poor age, was able to have a 454 big block that was stronger than the stock 1986 SBC I ran initially. And now, everything “bolts” up. Whatever route I go engine wise, as long as I stay big block, the template is already there…

 

[Shaun]

The Quadrajet carburetor is worth looking at also.
There are tiny air bleeds in the upper air horn that often plug up from dirt getting through the air cleaner.
Happens more often on 4x4 trucks used off road.
Also Idle down emulsion tubes that can plug up that effect the entire air fuel ratio curve idle to WOT.
Accessed by removing the upper air horn.
If the engine has been running poorly then it has seen engine backfire likley.
The Power piston is blow out proof in a Quadrajet. They often stick full down Lean or full up Rich position from carbon from engine backfires.

“The Quadrajet carburetor is worth looking at also.
There are tiny air bleeds in the upper air horn that often plug up from dirt getting through the air cleaner.
Happens more often on 4x4 trucks used off road.
Also Idle down emulsion tubes that can plug up that effect the entire air fuel ratio curve idle to WOT.
Accessed by removing the upper air horn.
If the engine has been running poorly then it has seen engine backfire likley.
The Power piston is blow out proof in a Quadrajet. They often stick full down Lean or full up Rich position from carbon from engine backfires.”



The Quadrajet gets rebuilt every few years or so. Full chem dip and all. I actually bounce back and fourth fom my Edelbrock 1901 and my Edelbrock 104. My specialty is actually Quadrajets, Dueljets, Varajets, and Thermoquads. I own over 50 of them. I have been rebuilding them for people since I was a kid (because no one else would before the internet forums revolution around 2006). Not only did I learn a lot on my own and reading books like Doug Roe, guys like Lars on the forums added a lot to my brain. Point in hand- I don’t think the carb is bad. Now can everyone please stop digging for engine issues? I feel like everyone is saying they will not offer cam advice on a bad engine, but the engine isn’t bad. I don’t know how to get that point across any clearer. As a matter of fact, for being such a low compression BB with a peanut cam it is actually quite impressive how good it moves. And remember, my truck is king of the hill size wise, not counting the Rockwell guys I am the big boy, a 1982 suburban with 1 ton axles- and the thing moves really good. I can effortlessly brake torque my 33” mud terrains with a powertrax and only 342’s. I could not do all of that with a healthy engine. I beat 6.0 Vortecs of the line, but then their power band kicks in and I am out of breath.

 

[Maniacmechanic1]

“The Quadrajet carburetor is worth looking at also.
There are tiny air bleeds in the upper air horn that often plug up from dirt getting through the air cleaner.
Happens more often on 4x4 trucks used off road.
Also Idle down emulsion tubes that can plug up that effect the entire air fuel ratio curve idle to WOT.
Accessed by removing the upper air horn.
If the engine has been running poorly then it has seen engine backfire likley.
The Power piston is blow out proof in a Quadrajet. They often stick full down Lean or full up Rich position from carbon from engine backfires.”



The Quadrajet gets rebuilt every few years or so. Full chem dip and all. I actually bounce back and fourth fom my Edelbrock 1901 and my Edelbrock 104. My specialty is actually Quadrajets, Dueljets, Varajets, and Thermoquads. I own over 50 of them. I have been rebuilding them for people since I was a kid (because no one else would before the internet forums revolution around 2006). Not only did I learn a lot on my own and reading books like Doug Roe, guys like Lars on the forums added a lot to my brain. Point in hand- I don’t think the carb is bad. Now can everyone please stop digging for engine issues? I feel like everyone is saying they will not offer cam advice on a bad engine, but the engine isn’t bad. I don’t know how to get that point across any clearer. As a matter of fact, for being such a low compression BB with a peanut cam it is actually quite impressive how good it moves. And remember, my truck is king of the hill size wise, not counting the Rockwell guys I am the big boy, a 1982 suburban with 1 ton axles- and the thing moves really good. I can effortlessly brake torque my 33” mud terrains with a powertrax and only 342’s. I could not do all of that with a healthy engine. I beat 6.0 Vortecs of the line, but then their power band kicks in and I am out of breath.

If the Engine Indeed does have only 7.1 to 8.4 :1 compression that was very Typical in the 1970's Disco Era your very limited to what can be done for Big Gains with a camshaft swap.
Usually here we work with at least 10.0:1 if not most of the time 11.0:1 static compression with aluminum heads.
Camshafts have 220-230 @ .050" duration.
6000 rpm Redline as Grumpy likes.
To do the same with a low compression engine like yours the engine will fall flat on its Face.

Some options are Isky 264 & 270 cams.
264 be best choice for low compression.
Power band will be very narrow much like a stock smogger disco era engine.

I have used a 280 Duration cam in past Pontiac 455.
110 lobe seperation.
Ran good.
3.23 gears. TH400 trans.
Tested cranking compression was 180 psi.
8.4 :1 static compression ratio.
Needed 93 octane gas to run right.

 

[Maniacmechanic1]

Have to do the math but for 87 octane in 454 Chevy with iron heads you need about 9.3 :1 static calculates compression to use a decent cam to get respectable power gains for money spent.

GRUMPY MAKES ALL SPEND MONEY HERE !
GET USED TO IT.

THE RACE DIAMOND PISTONS FOR MY 1970 TRANS AM RACE CAR I AM BUYING SOON...I WILL SPEND $1000-$1500 DOLLARS !

 

[Maniacmechanic1]

A built 572 that runs as it should will have over 800 Hp Normal aspirated.
You can only touch beat it with a High compression Race Fueled 110 motor octane Pontiac 455.
Normal aspirated no power adder heads up Race on the street.

 

[Shaun]

I would agree with you if it was not for the Caddy 500. I am actually a poncho guy myself (grass roots), but you just can't beet the displacement and high nickel content of the Caddy block. I actually have a smogger low compression 502. I rigged up a 1983 Regal T-Type turbo/center section/plenum, to it and rudimentary exhaust based off Chevy BB flanges. I have had it running on an engine stand with 10lbs of boost. I won't go any higher until I have a forged crank and heads that don't sport the Caddy curse. I hope to put it into an air boat one day.

"I've always suggested anyone contemplating changes to start from a verified and well understood basic engine" I am realizing I am in the wrong place. My toys are a little on the eclectic side, and Grumpy is kinda main stream 101 pete & repeat turned salesman. I guess I assumed he started out as a shade tree mechanic in his backyard once upon a time, possibly he just advanced strait to go and collected $200 without ever having to worry about graduating from playing with junkyard jewels (the trial and error stuff).

I don't have the money to compete with the "big boys", so I instead try to create "street-able" stuff from inexpensive readily available "junk" that will light up tires for what you pay for pistons. Lethal on the street, laughed at on the track. Don't get me wrong, I would love to be at that level one day, I just have not yet been kissed by the nepotism bug, completed a four year degree, nor am smart enough to have found my path to big money on my own or without aid of the the latter two.

I can tell you this much though, a larger cam is always better regardless of the compression ratio as long as you stay within the heads flow limits and keep the other factors such as duration and LSA in check. The peanut cams were products of pre-technology emission and fuel economy standards, not necessarily what was an ideal match up for the long block assembly. This is why simple cam swaps yield so much more power on the older stuff than the new- and a bone stock 4.8 LS can and will easily gain at least 40hp from just a cam swap (and tune). This logic is extremely helpful for the majority of the population, just not ideal for salesmen possessing customers with deep pockets. Why sell you parts to build an LY6 when I can sell you the LS3 for SO much more...

 

[Grumpy]

I spent decades of time building engines using salvage yards as the source for the majority of the components ( I used, and recommended)
I also spent and still spend a great deal of time building engines for myself and others, with huge restrictions on component cost and time.
Brian may think I like to point out high dollar parts....
no I hate having to spend money, on parts especially if theres a perfectly good component you can get at a local salvage yard that will work perfectly well in the application,
that may cost less than 10%-40% of what the aftermarket part may cost.... but I think excellent long term durability is far more important than throwing something together fast and cheaply, that may not last very long If you do the research, and check everything the first time...if you , do things correctly and you don,t need too do it over.
I also built more than a few (several dozen 389,400,421, 428 Pontiac back in the 1960s-1990s, and several more in the last few decades
, or as the old saying goes.. if you can't afford to do it correctly, how are you going to afford to do it over when it self destructs after the original parts selected fail.

yeah it frustrating at times..

here is one area of reality, where the difference lies between the best vs the better ,
and the all too frequent .... guys charging an exorbitant amount of money for inferior work,
you know, exactly what I'm saying if youve ever dealt with skilled machine shops,
and the better mechanics, and all too often, scam machine shops, and fly by night operations, that pop up and go out of business every few years,
and why good machinist and knowledgeable engine builder's ,are so hard to locate, and most have long wait times , too get quality work done..
and why it almost always costs considerably more, and frequently takes longer to have some shops and race teams, work on your car or engine,
its also why many guys get rather pissed off, when they see what it costs for a top quality builder to build any engine.
and without doubt guys in some shops see what the best shops charge and think.. hell, if the best shop in my area, charges that much I should be charging a good deal more,
and I can knock that out for a bit less and in less time and make a killing...... and why finding a good machinist and machine shop is a real challenge in most areas.
I can easily suggest a cam , but its a rather meaningless gesture, and all too frequently a waste of time and effort for both of us.
simply because, without verifying the facts, and this is where Id say the vast majority of internet web sites,
and the recommendations, you see being posted in them, all too often, go wrong far too frequently.
yeah its easy to assume the timings correct the true functional compression, in every cylinder is nearly identical,
(most guys measure, two or three cylinders and without a second thought ignore the rest,
and thus they, blissfully assume all the other cylinders must be the same or so close its a waste of effort,
, most guys fail to put in the effort, too measure the less easily accessed cylinders, thinking
(why bother its a P.I.T.A. and if the first two or three are fine so will the rest of them, )
and that is the attitude that will be used for other factors, yeah, most guys, and every other guy reading similar threads on a vast ocean of similar web sites,
all over the internet, skip over anything that is redundant or takes a bit of extra effort, they simply assume they know things that may or may not be true.
the vast majority of guys , are absolutely convinced, that verifying every measurement and clearance issue in their engine,
in each cylinder is so close that they are effectively duplicate in all areas,
yeah without any doubt... its a waste of time and effort, too do what most guys, will just be convinced is busy work,
yes most tuners and car owners are just like the vast majority and are convinced everything between all the cylinders have not changed are exactly as you and they remember them too be..
especially if they have taken the time and effort too do things correctly several times in the past and found that to be true in the past.
thats the difference between the 5%-10% of guys consistently posting the best and most

consistent time slips and lap times vs the guys that frequently win a few races,
but over a season or two, don,t consistently, year after year build a good reputation, for durability and consistently winning.

http://garage.grumpysperformance.com/index.php?threads/finding-a-machine-shop.321/

 

[Maniacmechanic1]

I would agree with you if it was not for the Caddy 500. I am actually a poncho guy myself (grass roots), but you just can't beet the displacement and high nickel content of the Caddy block. I actually have a smogger low compression 502. I rigged up a 1983 Regal T-Type turbo/center section/plenum, to it and rudimentary exhaust based off Chevy BB flanges. I have had it running on an engine stand with 10lbs of boost. I won't go any higher until I have a forged crank and heads that don't sport the Caddy curse. I hope to put it into an air boat one day.

"I've always suggested anyone contemplating changes to start from a verified and well understood basic engine" I am realizing I am in the wrong place. My toys are a little on the eclectic side, and Grumpy is kinda main stream 101 pete & repeat turned salesman. I guess I assumed he started out as a shade tree mechanic in his backyard once upon a time, possibly he just advanced strait to go and collected $200 without ever having to worry about graduating from playing with junkyard jewels (the trial and error stuff).

I don't have the money to compete with the "big boys", so I instead try to create "street-able" stuff from inexpensive readily available "junk" that will light up tires for what you pay for pistons. Lethal on the street, laughed at on the track. Don't get me wrong, I would love to be at that level one day, I just have not yet been kissed by the nepotism bug, completed a four year degree, nor am smart enough to have found my path to big money on my own or without aid of the the latter two.

I can tell you this much though, a larger cam is always better regardless of the compression ratio as long as you stay within the heads flow limits and keep the other factors such as duration and LSA in check. The peanut cams were products of pre-technology emission and fuel economy standards, not necessarily what was an ideal match up for the long block assembly. This is why simple cam swaps yield so much more power on the older stuff than the new- and a bone stock 4.8 LS can and will easily gain at least 40hp from just a cam swap (and tune). This logic is extremely helpful for the majority of the population, just not ideal for salesmen possessing customers with deep pockets. Why sell you parts to build an LY6 when I can sell you the LS3 for SO much more...

GRUMPY is A-ok.

I am a long time Pontiac Guy.
Have been since 1987.
I am also Chevy Guy. I own a 1987 Corvette.
I also like Oldsmobile V8.
Like some Ford's and a few Vintage Mopars also.

Going to play them you have to pay.
Still holds true today.

The Low compression and lack of money funds makes it impossible to give you 50-100-400 horsepower gains.