Building a S̶t̶r̶o̶n̶g̶ ̶3̶5̶0̶ 383 for Frank the Tank…

if you use the 70 cc heads and you can install the cam strait up vs 4 degrees advanced at the dot-to-dot install location that moves the close point to 55 degrees ABDC vs 51 in the calcs, or even retard it 4 degrees that moves it to 59 ABDC

( for each 4 degrees you retard the cam timing index ,in relation to crank rotation, the whole power curve will move about 200 rpm higher)

http://garage.grumpysperformance.co...ectly-and-get-it-to-last-cam-install-info.90/

http://garage.grumpysperformance.com/index.php?threads/checking-piston-to-valve-clearances.399/

http://garage.grumpysperformance.co...ng-cam-and-shifting-the-lca.10553/#post-44949

http://garage.grumpysperformance.com/index.php?threads/cam-degreeing.9010/#post-32126

http://garage.grumpysperformance.com/index.php?threads/how-to-pick-timing-gear-set.4548/#post-12699
 
Last edited:
Grumpy said:
if you use the 70 cc heads and you can install the cam strait up vs 4 degrees advanced at the dot-to-dot install location that moves the close point to 55 degrees ABDC vs 51 in the calcs, or even retard it 4 degrees that moves it to 59 ABDC

( for each 4 degrees you retard the cam timing index ,in relation to crank rotation, the whole power curve will move about 200 rpm higher)

http://garage.grumpysperformance.co...ectly-and-get-it-to-last-cam-install-info.90/

http://garage.grumpysperformance.com/index.php?threads/checking-piston-to-valve-clearances.399/

http://garage.grumpysperformance.co...ng-cam-and-shifting-the-lca.10553/#post-44949

http://garage.grumpysperformance.com/index.php?threads/cam-degreeing.9010/#post-32126

http://garage.grumpysperformance.com/index.php?threads/how-to-pick-timing-gear-set.4548/#post-12699
Click to expand...

Ah, ok.

So based on the data I have in the table so far, with 70cc heads, what cam characteristics combined with retarded timing would get me into a safe DCR?

I'll read the timing/degreeing info this evening. Thanks.
 
Anyone else have thoughts on how to proceed..? If I go with the 70cc heads? Of should I look for some larger? 72cc?
 
Tired here Jimmy.
Got the Wifee' & Back home.
Read Grumpys Links.
I will check them out Sunday morning .

You will need a Camshaft Degree Wheel Kit. $100-150 dollars.
Should Use a Cloyes True Roller Timing chain set. 9-position crankshaft sprocket.
Or Cloyes Hex- A - Just True Roller timing chain set. Infinate adjustable.

Tuning The Carb & Spark Timing will be critical .
Want to avoid detonation.
You can not always hear it.
You have a heavy car & tall gears.
Makes detonation more easily to happen.
 
Keeping the Intake Cool, Carburator Cool , & Fuel Feed line cool will help a lot.
 
87vette81big said:
Tired here Jimmy.
Got the Wifee' & Back home.
Read Grumpys Links.
I will check them out Sunday morning .

You will need a Camshaft Degree Wheel Kit. $100-150 dollars.
Should Use a Cloyes True Roller Timing chain set. 9-position crankshaft sprocket.
Or Cloyes Hex- A - Just True Roller timing chain set. Infinate adjustable.

Tuning The Carb & Spark Timing will be critical .
Want to avoid detonation.
You can not always hear it.
You have a heavy car & tall gears.
Makes detonation more easily to happen.
Click to expand...

87vette81big said:
Keeping the Intake Cool, Carburator Cool , & Fuel Feed line cool will help a lot.
Click to expand...

Yeah, thanks Brian. Get some sleep... ;)

I'm a bit worried now that I've made a mistake in the build to this point...

Can anyone explain where a typical 383 build would differ from mine to have lower DCR? Is it just a case of the cam specs?

I'm happy to focus on keeping everything cool as Brian recommends, but, I'd like to have a pretty safe build that is streetable...
 
Most don't pay attention to details Jimmy.
Only on Grumpys site here we do.
Get some rest.
Goodnight.
 
I would shop for heads, there are better head than the E Tec heads for similar prices. I would say if you had 4v relief pistons, I would look for a cam in the 230 - 235 dur .050 range. Something like these two cams, not telling you to pick them just the duration numbers and where it caused the Int Valve closing, maybe retard it 4 degrees and give you some more rpm up high. I would hunt for the heads, there is wide aray of chamber sizes out there. 67 cc heads would work with the second one, the mellings cam, retard it 4 degrees and ST/DY CRs would be like 10.8/8.25. You just have to hunt for them Jimmy. I spent awhile looking for mine, remember cam and heads are the heart/lungs of your engine, do choose wisely.
http://www.summitracing.com/parts/cca-12-246-3/overview/make/chevrolet
http://www.summitracing.com/parts/mel-22234/overview/make/chevrolet
 
You just have to look for the combo that will work for you! Indycars and I have similar builds. He has 70 cc heads and I have 64 cc heads, but my Static and Dynamic CRs and his are pretty similar. Mine is shorter on duration than his, but I have a heavier car than his T bucket so I opted to have my tq lower to pull my car off the line. Just take your time and ask for help when you need it. If you have the cam already, you can return it in favor of another that will match your heads and your plan.
 
busterrm said:
I would shop for heads, there are better head than the E Tec heads for similar prices. I would say if you had 4v relief pistons, I would look for a cam in the 230 - 235 dur .050 range. Something like these two cams, not telling you to pick them just the duration numbers and where it caused the Int Valve closing, maybe retard it 4 degrees and give you some more rpm up high. I would hunt for the heads, there is wide aray of chamber sizes out there. 67 cc heads would work with the second one, the mellings cam, retard it 4 degrees and ST/DY CRs would be like 10.8/8.25. You just have to hunt for them Jimmy. I spent awhile looking for mine, remember cam and heads are the heart/lungs of your engine, do choose wisely.
http://www.summitracing.com/parts/cca-12-246-3/overview/make/chevrolet
http://www.summitracing.com/parts/mel-22234/overview/make/chevrolet
Click to expand...

Thanks busterrm! It's good to see a couple of examples... I'm still a little uncertain about which figures to enter in the IVCA calc... Am I correct that I enter the adv durations (in the case of the first cam 274 and 286) and the LSA (110), then -4 for retarding it 4degrees? to get IVCA of 71?

Regarding the heads... I'm really limited in Australia with what fits in my budget.... I don't want to spend more than $2k Australian... so the best I seem to be able to afford is a set of E-Streets.. of maybe a set of Promaxx heads... Anything from US I get phucked by conversion and shipping.... $500+

busterrm said:
You just have to look for the combo that will work for you! Indycars and I have similar builds. He has 70 cc heads and I have 64 cc heads, but my Static and Dynamic CRs and his are pretty similar. Mine is shorter on duration than his, but I have a heavier car than his T bucket so I opted to have my tq lower to pull my car off the line. Just take your time and ask for help when you need it. If you have the cam already, you can return it in favor of another that will match your heads and your plan.
Click to expand...

I have a heavy car (think boat) and plan to run a th350 trans, probably 3.7 rear gears and a 29"ish rear tire..

I don't have the cam yet... So, I'm keen to get the heads and cam specs nailed down so I can get on the hunt for the parts.. While I have the cash... Otherwise it'll get spent...
 
Yes, when you put in the duration of the cam it is the advertised duration, then the LSA, that is usually between 106 - 114 its usually on the cam card you get with the cam. Most cams are ground 4 degrees advanced. Thats the number you put in not the amount of retarding the cam. When you put that in the calculator it will give you the Intake Valve Closing Angle, you put that number in the DCR calculator. Here's a set of Edelbrock RPM heads and Crane cam that would work:
http://www.summitracing.com/parts/edl-60739/overview/make/chevrolet
http://www.summitracing.com/parts/crn-110551/overview/make/chevrolet
 
That head and cam would give you 10.5 static and 8.22 dynamic CR. If your running a good quench and the fuel you spoke of you should be safe from detonation. You will have to retard that cam 4 degrees to get your DCR correct.
 
Last edited:
Retarding the cam comes after you have degreed the cam. Basically degreeing the cam is just checking if all the specs of the cam are correct, then retarding it moves the int closing angle to where you need it to obtain your DCR where it is needed to avoid detonation. For instance when I degreed my cam all the specs were right on except exhaust duration being off one degree, and my intake closing angle was short one degree but that worked in my favor. Retarded mine would have been 70, but was short one degree and after I retarded it it was 69 right where I really wanted it to be. Just shop and you'll find what you need.
 
I don't know why anyone is guesstimating the IVC angle, it' stated right on the
cam card at 71°. I even confirmed it with my Excel calculator on page 2.... see
both below. All calcs were done using the Crane 110911 camshaft.

Installation per the cam card yields a 4° advance, also know as installing Dot-To-Dot.

IVC_CamCard.JPG
IVC_ExcelCalc.JPG

Installing Straight UP(Engine # 2) is zero advance and yields a DCR of 8.18 CR,
right on the money. I'm running 8.25 DCR and 91 octane, with a slight problem
when I shut the engine off. It tends to sometimes fire 3-4 more times before it
stops. I've maximized the combustion chamber against detonation with polishing.

I did use a bigger "Gasket Diameter" (row 7), I think .040 inches bigger is close
enough, but won't allow the gasket to hang into the cylinder. That's only .020 inches
on the radius for each side. A head gasket hanging into the cylinder could cause a
hot spot and and result in pre-ignition.

White cells signify a change from the previous engine.

DCR_Calcs01.JPG

Sorry I've been out of town since Friday and this was my first chance to
comment on the latest posts.

.
 
I am just using the calculator to figure the IVC, I trust it more than anything because its more thorough. I was looking at the .050 numbers, crane puts them both on the cam card, I would run that cam dot to dot so the IVC is 71 to give a DCR of 7.95.
 
Last edited:
It just depends on how conservative you want to be. If it was me, I would go with
the 64 cc chambers for Engine #2. But of course that's just me talking. Remember
he has access to 93-94 octane fuel.
 
just a thought!
every choice is a compromise
and these are random power figures not related to your build specifically
if you go with the larger combustion chamber and slightly lower compression your less likely to run into detonation issues that can cause a great deal of damage, the cost in power would likely be about 4% less torque for EACH full compression ratio, so if for example you were going from 8:1 to 8.2:1 dynamic compression you could reasonably expect to see a .2% reduction, in torque.
lets say the engine combo produced 450 ft lbs at the higher 8.2:1 dynamic compression, and peak torque was at 4700 rpm, and at 5600 rpm it had dropped to 420 ft lbs=that would be entered into the hp formula
tq x rpm/5252=hp, that equals 447.8 hp
if we has .2% less torque, roughly 5 ft lbs less=442 peak hp for a bit of insurance that youve built an engine with less tendency to get into detonation

whats that worth in ET?
lets say the car weights 3400 lbs

here you might be taking a chance at busting a ring or piston due to detonation
Your ET / MPH computed from your vehicle weight of 3400 pounds and HP of 447.8 is 11.45 seconds and MPH of 118.05 MPH.

Your ET / MPH computed from your vehicle weight of 3400 pounds and HP of 442 is 11.50 seconds and MPH of 117.53 MPH
here you might be taking a significantly lower chance at busting a ring or piston due to detonation
 
Indycars said:
It just depends on how conservative you want to be. If it was me, I would go with
the 64 cc chambers for Engine #2. But of course that's just me talking. Remember
he has access to 93-94 octane fuel.
Click to expand...
Yeah, I was thinking the same thing, better gas than us!
 
Indycars said:
I don't know why anyone is guesstimating the IVC angle, it' stated right on the
cam card at 71°. I even confirmed it with my Excel calculator on page 2.... see
both below. All calcs were done using the Crane 110911 camshaft.

Installation per the cam card yields a 4° advance, also know as installing Dot-To-Dot.

View attachment 6999
View attachment 7000

Installing Straight UP(Engine # 2) is zero advance and yields a DCR of 8.18 CR,
right on the money. I'm running 8.25 DCR and 91 octane, with a slight problem
when I shut the engine off. It tends to sometimes fire 3-4 more times before it
stops. I've maximized the combustion chamber against detonation with polishing.

I did use a bigger "Gasket Diameter" (row 7), I think .040 inches bigger is close
enough, but won't allow the gasket to hang into the cylinder. That's only .020 inches
on the radius for each side. A head gasket hanging into the cylinder could cause a
hot spot and and result in pre-ignition.

White cells signify a change from the previous engine.

View attachment 6997

Sorry I've been out of town since Friday and this was my first chance to
comment on the latest posts.

.
Click to expand...

Hi Rick!

Ha! I was guesstimating because I wasn't quite sure how the calculator worked... and Grumpy's add 15 sounded pretty straight forward... Now I see how you've used the number from the card (duh..) and also the calc comes out the same, it makes more sense to me...:) Thanks.

I feel like my half understanding led me to panic... but now I see your examples it looks pretty good.. There are options with cams like this, to adjust it to work..

How do I find a hydraulic cam with the same characteristics as the Crane 110911 (its a solid)? Would you use exact same numbers? Or, do they need changing when using different style of lifters? Also, keeping in mind the E-Streets have valve spring maximum lift: .550"
 
You must log in or register to reply here.
Back
Top