383 Stealthram

There is not didly for valve lift with modern aluminum heads.
Going to use 1.65:1 ratio rockers Ctower Cams makes them for SBC .
Pontiac RA4 Ratio Rocker too
 
Ok I have a simulation run.
Pretty good for a Nitrous cam profile used Normal Aspirated.
Think Power figures are 40-50hp high.
I can not simulate Tri Y Headers.
They typical are done giving torque g add ins over 4-tube Headers by 4500 rpms.
Used small tube headers open exhaust.
Tunnel Ram 1000 cfm.
Can't do a Holley Stealth Ram.
 
Its packing alot of indicated calculated cylinder pressure.
I chose 10.25:1 static compression ratio.

Really too high for pump 93.
Wants 110 octane Race gas or E85 Corn fuel.

Nitrous oxide used probably 114 octane needed.
 
If you bought this camshaft profile what likely needs to be done is used D-cup Dished pistons -15 cc be a start to calculate with.
Good set of ICON Forged 2618 they are nice for the money.
 
Everything optimal with induction and exhaust it has a very high volumetric efficiency for a Street engine with the AFR Eliminator heads with the Nitrous cam chosen.
In theory.
 
Detonation is no Fun Street Driving.
E85 I like but it's a high maintenance fuel to use on the street.

Need an exact parts list you have now in your possession.
 
https://pin.it/5jp4aJv

I completed another DD2000 engine simulation run this morning.
I dropped static compression ratio down to 8.4 : 1 ,
Loss of 50 Hp from 10.25:1 .
But still at 501 hp.
Switched to single plane intake and just 1 hp difference.
Looking at BEMP Brake Effective Mean Pressure and its just barely 93 RM/2 Pump gas compatible with 8.4:1 static compression ratio used.

It's the Right static compression ratio 8.4:1 to use pump gas 93 with your chosen bought Nitous Oxide Camshaft.

Your Cam was designed for 114-120 Motor Octane Race Gas with a +250 Hp Nitrous Hit or more maybe to +400 Hp more Fogger System all in by 6000-6500 Rpms
Probably 1/8 mile Drag Nitrous Cam using 3.23 - 4 .10 gears with 27" - 31.0" Tall Rear Tires Tubo 400 Transmission used.
 
3rd and 4 th Gen F-body are lighter but the Unibody is tapped out around 425 hp stock.
Not as strong as 2nd Gen F-body.
But lots of Chassis parts are made to easily bolt on 3red and 4th gen.
 
Well I don't know about the compression ratio. I was under the impression that this was the most common setup for stroked small block one piece rear seal blocks . With the aluminum heads and an off the shelf mild cam with almost 113 degree lsa, everyone talks about how with a 2200 or 2300 stall this motor should be able to run well on 87 octane. Why now should it need race gas? I talked to AFR and they never mentioned I would need race gas. They said it would rev like crazy due to strong torque and be good up to 6000 rpm or so. I have the big chamber heads. Their purpose is to lower the compression. The only thought I have is with flat top Pistons with valve reliefs whether my valves will hit with 1.6 ratio rockers and whether the exhaust will be mellow sounding enough. How did you calculate the compression for the 74.5 cc heads?
 
CWash2 said:
Well I don't know about the compression ratio. I was under the impression that this was the most common setup for stroked small block one piece rear seal blocks . With the aluminum heads and an off the shelf mild cam with almost 113 degree lsa, everyone talks about how with a 2200 or 2300 stall this motor should be able to run well on 87 octane. Why now should it need race gas? I talked to AFR and they never mentioned I would need race gas. They said it would rev like crazy due to strong torque and be good up to 6000 rpm or so. I have the big chamber heads. Their purpose is to lower the compression. The only thought I have is with flat top Pistons with valve reliefs whether my valves will hit with 1.6 ratio rockers and whether the exhaust will be mellow sounding enough. How did you calculate the compression for the 74.5 cc heads?
Click to expand...
The cam has a pretty tight intake Centerline of 108 degrees.
113 LSA is an average of intake centerline plus the exhaust centerline divided by 2.
You never stated what Pistons you have, exact Valve relief CC Volume.
Quench height your using.
Piston compression or pun setting height.
Can get very detailed.
I had to guess what compression ratio.
Chose 10.25:1 to start.
 
190-195 psi IMEP BEMP is about Max on pump gas 93 with full Ignition advance.
Desktop Dyno does the calculated values automatically after entering data.
What it shows.
Have to look but I recall 205 psi BEMP with 8.4:1 static compression ratio, really too high yet for Pump gas 93 but can maybe pull it off with a perfect tune.

It's the camshaft that you chose that is causing issues,
Typically can run 11.0-13.0 :1 static compression ratio with modern aluminum heads on a Small block Chevy with right camshaft profile.
 
Modern Full Race Pistons by Racetech, CP Carillo, Diamond Pistons, Ross, JE Are usually made for up to .750" valve lifts off the shelf.
Still have to check P.T.V.O.C. on engine mockup assembly.
 
There are 2 viable options get Different Forged pistons with a D-cup dish around -15 cc made to drop static compression ratio intentional.
Buy Roots Blower Supercharged dished pistons of past for static compression 7.0-7.5 :1 meant for 15psi + boost.

Or sell your Nitrous camshaft or Return it.
Choose another Normal Aspirated Camshaft.

I Love Iskenderien Cams.
Always had Fantastic results with and Zero parts failures.

Howard's cams are Favorite of many modern Chevy Small Block guys today Drag Racing No Prep .
Price is affordable.

They claim Howard's Roller lifters are made in the USA.

Isky Roller Cams are usually Full Drag Race and Dirt Oval Track Racing 7000-10,000 rpms.
 
108 LCA is probably tightest that can be done with modern EFI Before intake manifold is too low EFI Tuners just can not make them idle with low intake manifold readings.

108- 110-112 LCA
 
I think I might try an EFI computer strolled cam about 224/230. From YouTube videos the idle seems mild enough, the split is just right for AFR heads, and the lsa and lift are just right. Also I have upgraded double springs. I think maybe I might have to break the cam in with single springs?
 
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