496ci revamped

Maniacmechanic1 said:
W

What is the LCA on your old cam ?
What headers do you have again ?
496 Is like a Pontiac 455.
4.25 vs 4.21 inch strokes.
More cubed 496 and more to fill and scavange.
Seems like an exhaust issue.
Big Chevies love 5.000 inch collectors.
No exhaust.
5 inch exhaust Dumps or custom 5 inch .
Click to expand...
112°
37"long scavenger series 2" tubes
Ceramic coated with 3 1/2" collector
3" exhaust all the way back
That by my research on here should support 679hp.
Howard's said two options shim the springs which will be hard on lifters
Or more duration on the cam.Screenshot_20180529-073143.png
 
My understanding from comp cams Guy
Said it had something to do with compression being 11.2 to one
Cam with 236 is better matched with 10:1
To 10.5:1 11:1 thing's start changing
And need more overlap really needs more like 83 degrees on 500ci 11.2:1
Efi 72 is max and if not for total seal gapless rings it probably wouldn't work

Howard's didn't go into details
But when I first ordered cam the goal was 10.5:1 but after taking motor down
And seeing quench was incorrect
I had to use thinner head gasket
Which upped compression.
Wish I had found you guys before I bought parts.
I probably would have done a better job
At getting right parts in first place.
I'm not out much, a lot of stuff I was able to sell and recover a lot of my cost.
 
Last edited:
Speedlink1973 said:
112°
37"long scavenger series 2" tubes
Ceramic coated with 3 1/2" collector
3" exhaust all the way back
That by my research on here should support 679hp.
Howard's said two options shim the springs which will be hard on lifters
Or more duration on the cam.View attachment 12115
Click to expand...
Get the present cam specs for me. Around 5-6 pm I will run DD2000 for You.
I need Valve lifts with present rockers.
Single or Dual Plane intake.
IVO, IVC, EVO, EVC @.050 Hydro .
Solid Usually @ .020 today.

Just going to use Full Race Heads option.
Going to look at power band open exhaust and closed exhaust.

Bullet Race Mufflers Super Dynomax, Borla XR1 & Hooker Aero chambers are best for Street today.
Hooker Aero chambers 3 inch I want yet to replace the original Flowmaster 2-chamber mufflers on TA.

GOT same layout.
2,inch primary.
3-1/2 collectors.
3 inch Torque Tech mandrel bent exhaust to rear bumber.
Torque Tech gone now owner retired.
 
Speedlink1973 said:
My understanding from comp cams Guy
Said it had something to do with compression being 11.2 to one
Cam with 236 is better matched with 10:1
To 10.5:1 11:1 thing's start changing
And need more overlap really needs more like 83 degrees on 500ci 11.2:1
Efi 72 is max and if not for rings it probably wouldn't work
Click to expand...
Should behave real close to Ponch 455 and 496.
You have more cubes to feed air and fuel.
700 Hp had easier with smaller cam specs other than valve lift.
I don't need High valve lifts .700 - 1.000 inch with my heads. I do need Race cam full to perform optimal.
 
Old cam, and same heads
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Maniacmechanic1 said:
Driving.
Working with a Flow window of
.200-..550-.600 area. Higher lift cam would be of benefit.
I see 700-720 Hp max without using ultra high revs.
Click to expand...
6500 is magic number that alludes me.
28" tire 4.11 gear 1/4 mile = 6329rpms

I've changed retainers and locks to titanium for better valve control
I've added 200 cfm to throttle body
For more air. Changed push rods exhaust push rods .150 longer intake .100 longer
Pypes 3" mandrel bent race pro mufflers they clam they flow 701 cfm each at 3"
6100 flat 6127 it falls off hard
Nothing left.

1.7 rockers
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Speedlink1973 said:
6500 is magic number that alludes me.
28" tire 4.11 gear 1/4 mile = 6329rpms

I've changed retainers and locks to titanium for better valve control
I've added 200 cfm to throttle body
For more air. Changed push rods exhaust push rods .150 longer intake .100 longer
Pypes 3" mandrel bent race pro mufflers they clam they flow 701 cfm each at 3"
6100 flat 6127 it falls off hard
Nothing left.

1.7 rockers
index.php
Click to expand...
It may be the Mufflers.
I know the Flowmasters cost me some power in the past.
Race Cam so it still revved high with ease.

Trans Am guys use those Pypes Mufflers.
99 % stuck in 15's & 13's.....Long story...some have 400 CFM ported E heads.
I tried they hate drag racers that group...Pro Tour drive slow what they do.
1 Drag racer left & I taught him....From Detroit & a Real Street Racer.
He messes with them daily. LOL

Get to work soon, at home.
 
Maniacmechanic1 said:
It may be the Mufflers.
I know the Flowmasters cost me some power in the past.
Race Cam so it still revved high with ease.

Trans Am guys use those Pypes Mufflers.
99 % stuck in 15's & 13's.....Long story...some have 400 CFM ported E heads.
I tried they hate drag racers that group...Pro Tour drive slow what they do.
1 Drag racer left & I taught him....From Detroit & a Real Street Racer.
He messes with them daily. LOL

Get to work soon, at home.
Click to expand...
Let me know if you need anything else

Thanks again
 
Ok I ran a simulation.
I entered your AFR 290 Oval Port Heads , Made an Airflow file & used it.
There is enough VE present to keep pulling hard to 8000 RPMs with your present Cam.
HP peaks out a 6500 RPM's.
VE peaks out 88.5 % @ 5500 RPM.
Torque peak is 601 Ft/lbs @ 5,000.
Hp is 656 @ 6500 rpm.

Seems to be a real broad torque curve.
Not really needed drag racing in a fairly light car like your 1st gen Camaro with Drag gears now & a 496 BBC.

Different methodologies used to get the right power hit torque curve & HP where wanted drag race.

Open Big Tube headers used.
Save, Load to Imigur & then post results this simulation run.
 
rp3Dw1c.png
E5syxS0.png
HLoDQWE.png


With Mufflers Robert & Grumpy.
Around 600 HP solid on tap.
Going to vary alot by different style mufflers....hard to tell without actual reviews, testing at tracks, WOT speed runs if geared tall to do so, of course street battles done.
 
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