496ci revamped

[Speedlink1973]

Cam specs are mild for such a Big Ci. Engine.
Will make Superb torque.
Not a Supercharger cam . Lobe centers too tight.
Ok for Nitrous a small shot 125-150 .

What I see.

Oh supercharger is a year or two away

I based it off one of those Mark Jones
"Vortech performance" motors
Very similar build if those numbers are right .
I'm at a bit more compression
Than this motor and a few tweaks as well
And yes I figured Nos would come before supercharger
It why I gapped the gapless rings to .024
And thermal coated piston just in case I want to hit it with a bit of Nos

 

[Speedlink1973]

I hope you bought thee correct high heat versions?
the next time you pull the engine down youll see all the crap they collected
http://garage.grumpysperformance.com/index.php?threads/magnets.120/#post-76617

Yep good up to 150 degrees Celsius or 302 degrees fahrenheit

 

[Indycars]

If you can add the info below I can get a more accurate simulation. Need to get all the info in the
first run because every run after will be compared to the first run.

Heads Make and Model Number.
Flow numbers thru out the lift range, not just at .700. [So I can add it to my library.]
Cam Make and Model Number or Cam Card. [So I can add it to my library.]
Cam Type: Hydraulic or Solid, Flat or Roller

 

[Speedlink1973]

If you can add the info below I can get a more accurate simulation. Need to get all the info in the
first run because every run after will be compared to the first run.

Heads Make and Model Number.
Flow numbers thru out the lift range, not just at .700. [So I can add it to my library.]
Cam Make and Model Number or Cam Card. [So I can add it to my library.]
Cam Type: Hydraulic or Solid, Flat or Roller

It's a hydraulic roller springs
Seat pressure is 145 and 380 on the nose
Heads are AFR 290 oval port 112cc chamber fully CNC screen shot has all flow numbers, but I'm betting exhaust will flow a bit better now they are polished.

 

[Grumpy]

everything looks well matched,
in fact ,looking over the parts list,
its about the ideal combo for brisk street performance,
and instant responsive performance.

Id have selected different heads ,and added a bit more compression,
and maybe 7-8 degrees more cam duration
but those originally posted components are certainly close to ideal.
(especially for street/strip use)
Id have gone this route on heads
https://www.airflowresearch.com/315cc-bbc-rectangle-port-cylinder-head/

another option

 

[Speedlink1973]

everything looks well matched

Hey Grumpy, you think the stud girdles
And belt drive will help valve train stability at these RPM's
Or not worth it?
I under the impression most likely valve train causes most catastrophic failures

Oh I did go with single plane intake
Victor jr 454-O and port matched it, being that said, should I still try to use 1" spacer we discussed
To use on dual plane intake?

 

[Grumpy]

rocker stud girdles are almost mandatory ,
belt drive is nice but certainly not mandatory,
cloyes timing chains,
(especially if swapped out for a new replacement occasionally , work fine.)

 

[Indycars]

.
DynoSim5 tell me that the cam is installed 4° advanced when the intake centerline is 108°.





What would you like to see next ???

.

 

[Grumpy]

Rick, the same specs but the other heads
315cc BBC
https://www.airflowresearch.com/315cc-bbc-rectangle-port-cylinder-head/
.200 .300 .400 .500 .600 .700 .800
Int 169 249 312 353 380 386 387
Exh 146 184 238 271 296 310 315
Test conducted at 28" of water (pressure) on Superflow 600

I got asked in a private e-mail ,
"why I would prefer the 315cc small rectangle port intake and single plane intake vs the large 290cc oval port AFR heads on that 496 BBC?"
and what other changes if any Id prefer?
Crane Cams 139791
https://www.summitracing.com/search...ywordMatch&SortOrder=Ascending&keyword=139791
I simply stated that I was very willing to trade off some tiny bit off-idle and mid rpm torque that the selected oval port heads might provide , Id be willing to boost compression to 11:1 and need to run only race octane fuel, even if its installed 4 degrees retarded (which id do for sure)
for a bit more peak power, because , having built several dozen similar BBC 477-,489-496 and 502,
from long experience, I know that when your driving the car on the street at part throttle ,
you have zero need for more lower rpm torque to get the car moving, or brisk acceleration,
but if your intending on holding the throttle wide open, the very minor trade-off favoring better breathing slightly larger 315cc ports,
do provide, in the 4000 rpm-6000 rpm, range, a bit more useful power for passing, and brisk acceleration, using the mid-through upper rpm range power band.
the difference makes the car less street-able but certainly if correctly matched to a 3200 stall converter and a full manual 4l80e with its over drive top gear and maybe a 3.54:1 rear gear ratio, in my opinion a better match to my c4 corvette.


related info
https://www.hotrod.com/articles/crane-cams-dyno/

http://garage.grumpysperformance.co...ng-combustion-chambers.2630/page-3#post-77963

http://garage.grumpysperformance.co...sue-based-on-mis-information.6414/#post-49916

http://garage.grumpysperformance.co...t-intake-on-oval-port-heads.13146/#post-71777

http://garage.grumpysperformance.com/index.php?threads/another-496bbc.5123/

http://garage.grumpysperformance.co...g-block-head-comparison.319/page-2#post-49217

http://garage.grumpysperformance.com/index.php?threads/build-a-496-stroker-bbc.101/#post-49427

http://garage.grumpysperformance.co...-intake-for-a-496-bbc-engine.5690/#post-17282

http://garage.grumpysperformance.co...gine-build-up-for-the-street.3153/#post-12475

http://garage.grumpysperformance.co...lock-chevy-heads-pictures-info.410/#post-8312

http://garage.grumpysperformance.co...pgrading-your-454-bbc-to-a-496.992/#post-1762

http://garage.grumpysperformance.com/index.php?threads/rectangle-port-intake-on-oval-port-heads.560/

 

[Speedlink1973]

.
DynoSim5 tell me that the cam is installed 4° advanced when the intake centerline is 108°.

View attachment 10366

View attachment 10367

What would you like to see next ???

.

Looks pretty awesome to me,
I wonder why my app virtual dyno
Has it retarded -4 degrees?
Cause those numbers look way better.
My understanding is - or retarded will gain hp but lose torque
Wonder what -2 looks like
Guess I'm asking so I know where to start
Once it's done and in the car I plan on
Breaking it in then off the chassis dyno
For some fine tuning those numbers will get posted on here as well.

 

[Speedlink1973]

Thanks again for running dyno simulator!!

 

[Maniacmechanic1]

Thanks again for running dyno simulator!!

Rick did not show the hardware used.
Single or Daul plane intake.
What CFM carb.
Open Big Tube Race Headers no mufflers used.
Or Typical small tube headers with Street Mufflers.

Results can be much different in street trim.
Down 50-150 Horsepower.

I do the same in the Trans Am world.
Do simulation in Street trim and all parts known inputed.

Unless Drag Racers.
So far in 2 years there only has been 1 other drag racer like me.

Just keep in mind results can vary.

Best to use 1/8 & 1/4 Mile Mph from timeslips.
Calculate HP from it.

 

[Speedlink1973]

Rick did not show the hardware used.
Single or Daul plane intake.
What CFM carb.
Open Big Tube Race Headers no mufflers used.
Or Typical small tube headers with Street Mufflers.

Results can be much different in street trim.
Down 50-150 Horsepower.

I do the same in the Trans Am world.
Do simulation in Street trim and all parts known inputed.

Unless Drag Racers.
So far in 2 years there only has been 1 other drag racer like me.

Just keep in mind results can vary.

Best to use 1/8 & 1/4 Mile Mph from timeslips.
Calculate UP from it.

2" ceramic coated 37" long tube flow master scavenger series
The exhaust is Stainless 3" X pipe
By pypes, it's the race pro series, they're supposed to flow 701cfm

Rick did ask if it was a single plane or dual plane intake,
Which I did switch to a single plane intake victor jr 454 O I match port
The intake

yes these are just simulations, I was just looking for a curve to get me in the ballpark on were to start
Adjusting timing on cam.
Thanks for bringing it up about exhaust
And making sure I don't use this as the gospel

 

[Maniacmechanic1]

2" ceramic coated 37" long tube flow master scavenger series
The exhaust is Stainless 3" X pipe
By pypes, it's the race pro series, they're supposed to flow 701cfm

Rick did ask if it was a single plane or dual plane intake,
Which I did switch to a single plane intake victor jr 454 O

yes these are just simulations, I was just looking for a curve to get me in the ballpark on were to start
Adjusting timing on cam.
Thanks for bringing it up about exhaust
And making sure I don't use this as the gospel

If it does not perform as expected 1st thing to do is unhook the exhaust.
Retry ET and Mph at the track.

Pypes is real big in the Trans Am world.
Just Ok.

Borla XR1 Race mufflers one of the Best.
Dynomax Bullet Race Mufflers best.

Big Chevy needs to breath free.
Usually takes 4-5 inch exhaust.

 

[Indycars]

Rick, the same specs but the other heads
315cc BBC
https://www.airflowresearch.com/315cc-bbc-rectangle-port-cylinder-head/
.200 .300 .400 .500 .600 .700 .800
Int 169 249 312 353 380 386 387
Exh 146 184 238 271 296 310 315
Test conducted at 28" of water (pressure) on Superflow 600

Ok, as you can see the combustion chamber size changed. Since the comparison was about the port
size, I assumed a change in pistons that would keep the SCR at 11.22 .

DynoSim5 does not distinguish between a carburetor and EFI.



This time to keep Brian happy, I also posted the engine details! You should look them over and make
sure they reflect the engine that's in your head.

 

[Indycars]

One of the choices I have to make and it's not always a black-and-white choice is the combustion
chamber type. This along with other choices do make a difference.




The complete DynoSim5 manual is available below. I couldn't post it here since it's 18 MB.

http://72.198.60.106:8080/share.cgi?ssid=0476hO1

.

 

[Grumpy]

thank you Rick!
could I impose just a bit more and ask you to play with the specs , jump to a 11:1 compression, and use a crane 139791 cam retarded 4 degrees

 

[Indycars]

I really need the cam card to do it right! They make it so hard to find!!!

I have about 100 cam cards now, but not that one.

 

[Grumpy]

yeah I found it very hard to locate also, Ill continue to look.
bingo, .. info posted above

 

[Speedlink1973]

Rick, the same specs but the other heads
315cc BBC
https://www.airflowresearch.com/315cc-bbc-rectangle-port-cylinder-head/
.200 .300 .400 .500 .600 .700 .800
Int 169 249 312 353 380 386 387
Exh 146 184 238 271 296 310 315
Test conducted at 28" of water (pressure) on Superflow 600

I got asked in a private e-mail ,
"why I would prefer the 315cc small rectangle port intake and single plane intake vs the large 290cc oval port AFR heads on that 496 BBC?"
and what other changes if any Id prefer?
Crane Cams 139791
https://www.summitracing.com/search...ywordMatch&SortOrder=Ascending&keyword=139791
I simply stated that I was very willing to trade off some tiny bit off-idle and mid rpm torque that the selected oval port heads might provide , Id be willing to boost compression to 11:1 and need to run only race octane fuel, even if its installed 4 degrees retarded (which id do for sure)
for a bit more peak power, because , having built several dozen similar BBC 477-,489-496 and 502,
from long experience, I know that when your driving the car on the street at part throttle ,
you have zero need for more lower rpm torque to get the car moving, or brisk acceleration,
but if your intending on holding the throttle wide open, the very minor trade-off favoring better breathing slightly larger 315cc ports,
do provide, in the 4000 rpm-6000 rpm, range, a bit more useful power for passing, and brisk acceleration, using the mid-through upper rpm range power band.
the difference makes the car less street-able but certainly if correctly matched to a 3200 stall converter and a full manual 4l80e with its over drive top gear and maybe a 3.54:1 rear gear ratio, in my opinion a better match to my c4 corvette.


related info
https://www.hotrod.com/articles/crane-cams-dyno/

http://garage.grumpysperformance.co...ng-combustion-chambers.2630/page-3#post-77963

http://garage.grumpysperformance.co...sue-based-on-mis-information.6414/#post-49916

http://garage.grumpysperformance.co...t-intake-on-oval-port-heads.13146/#post-71777

http://garage.grumpysperformance.com/index.php?threads/another-496bbc.5123/

http://garage.grumpysperformance.co...g-block-head-comparison.319/page-2#post-49217

http://garage.grumpysperformance.com/index.php?threads/build-a-496-stroker-bbc.101/#post-49427

http://garage.grumpysperformance.co...-intake-for-a-496-bbc-engine.5690/#post-17282

http://garage.grumpysperformance.co...gine-build-up-for-the-street.3153/#post-12475

http://garage.grumpysperformance.co...lock-chevy-heads-pictures-info.410/#post-8312

http://garage.grumpysperformance.co...pgrading-your-454-bbc-to-a-496.992/#post-1762

http://garage.grumpysperformance.com/index.php?threads/rectangle-port-intake-on-oval-port-heads.560/

I bet this head would do good as well