I need more performance out of my 383...NOW!!!

[IROCker]

Bought an '86 IROC with 14,000 miles on the 383 stroker, T-56 tranny, and 3.73 rear. I've got the TPIS Mini-Ram injection system, 11.5:1 Keith Black hypereutectic pistons, Eagle crank and rods, perfect cam, MSD ignition, billet distributor, great headers, alum driveshaft, new rubber...THE WORKS! But the only problem is that I spoke with a guy with almost the exact same motor, little more beefy, and he was running low 11s, while I'm still running mid-12s.

I'm only 20, so I don't know all the odds n' ends of maximizing performance yet, so a little advice would be much appreciated!

[IROCker]

Here's some more specific parts that may need upgraded:
350 block stroked, bored, and balanced to 383ci
AFR 195 aluminum heads, 1.6 rockers, perfect cam (not changing)
Keith Black hypereutectic pistons 11.5:1 compression
Eagle crankshaft and Eagle connecting rods
TPIS Mini-Ram fuel injection system with 24 lb/hr injectors and 58mm throttle
MSD ignition, billet distributor w/8.8 wiring
Borla stainless tuneable exhaust system with thorley headers and quad tips
Lingenfelter flywheel
T-56 transmission, aluminum driveshaft, 3.73 rear end w/posi
centerforce clutch, hurst shifter

It appears like I've got it maxed out, but I can feel that there is more to this engine than what I'm getting out of it. Maybe I just need to have it dyno tuned and precisely timed to its optimum conditions, but I don't know what else I can do. But it's not running bad at all, I'm just a perfectionist. Thanks for any insight.

[wolfdogs]

how's youre 60' time?

its not always the car you know

[N20LT4Bird]

how's youre 60' time?

its not always the car you know

.....and what are the specs on the "perfect cam"? Are the heads ported at all?

[Injuneer]

You need to look at the "MPH" on the timeslip, not the "ET". MPH is a good measure of how much HP the engine is making, ET tells you how well the car and the driver "use" the HP that's available. Post a complete timeslip, including 60-ft time and 1/8-mile MPH and ET. What's the elevation where you run? What are typical weather conditions? I was so clumsy and inept with my T56/Street Twin setup that (running NA) I had a hard time breaking into the 11's, even though the car would run 115-117MPH. With the TH400, and 30 less rwHP, it runs mid-11's.

It shouldn't be hard to hit 11's with a 383. If the AFR's are "out of the box", they might need a little cleanup on the porting. What are the specs on the cam you don't want to change? Your 24# injectors may be limiting you. Who did the tune? Are you running mass air or speed density? What fuel do you run?

[brandon1934]

Some N02 should do the trick.

[95TransAm]

Some N02 should do the trick.

Maybe at the dentist's office

[IROCker]

Thanks for all the help. Here's some specifics to my parts:
CAMSHAFT: HYD. valve adjustment, .502/.510 valve lift, 280/288 tappet lift
duration @ .050 224/230; lobe lift .335/.340

HEADS: AFR 195 vette plug/74cc straight out of the box.

I run in Missouri and the air is always thick and saturated, but sunny most of the time. Pretty much the max octane they sell is 91, and the only place I can find with 93 is the cheap stuff. I would run 97 with the pistons I've got if I could, but obviously I can't. And the nearest BP is 25 miles away! Pretty much sucks out here.

[IROCker]

And like I said previously, I am certainly no pro driver either. That could be the problem. But the Lunati 383 kit I saw the other day sure looked tempting.

[N20LT4Bird]

And like I said previously, I am certainly no pro driver either. That could be the problem. But the Lunati 383 kit I saw the other day sure looked tempting.

The cam looks pretty good. But, as Fred has said, its trap speed that gives an indication of power, not ET. So, instead of comparing Et's with the friend that has the similiar set-up, compare trap speed. If your running over 112-113 mph, you've got an 11 second capable car. Or, you may be running 122 mph and barely brushing the 11's cause you suck......

[95TransAm]

If your running over 112-113 mph, you've got an 11 second capable car. Or, you may be running 122 mph and barely brushing the 11's cause you suck......

Sorry to hijack, but you're last comment made me curious. When you ran your car, were you using street tires? Also, I read that the new Z06 when tested ran an 11.5 at 128 on street tires obviously. I'm assuming that 500hp on a 3,130 lb. automobile has a pretty hard time hooking up to obtain this . With a trap like that, do you think it's a high 10 second car with slicks?