Chevy Impala SS Forum banner
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Discussion Starter · #1 ·
My buddy is rebuilding the stroker out of his 95' Z28. He built the engine last year, but the timing chain let go forcing a rebuild. He originally went with the LT4 cam, but talked with the local machine shop and decided to go "bigger". They had Comp grind him a cam, but after looking at the specs (which I admit I know little about) I wonder how good a choice it is. Actually, I'm just being a nib-sh!t...

The car is a 383 stroker, LT4 heads and intake, coated Hooker longtubes, Holly throttle body and 30# injectors (I think), Herter tune (mail order).

The specs off the card are below:

Grind # LT1 3018S/3039S HR113.0

Intake Exhaust
Gross valve lift .585 .580
Dur. @ .006 tappett lift 292 300

Open Close
Valve timing @ .050 int:12 BTDC 50 ABDC
exh:61 BBDC 7 ATDC

These specs are for cam installed @ 109.0 intake centerline

Intake Exhaust
Duration @ .050 242 248
Lobe lift .3660 .3630
Lobe seperation 113.0

After looking at some other cam specs, I think it will idle like crap and have very little vaccum.

Discuss.
 
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Discussion Starter · #2 ·
That is BIG even by the often too large standards on the f-body boards. The stroker will help tame it some but it is still going to be a monster and a PITA to get tuned truely well.
 
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Discussion Starter · #3 ·
And I thought I had a big cam
!

Yeah.....that's gonna be a tough tune.....the idle may not be to bad with the stroker.....but there will probably be some vacuum issues. I'd consider a vacuum canister with that cam.

KW
 
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Discussion Starter · #4 ·
I have a cam in a 383 which has a very similar duration on a noticably tighter lsa. It pulls 12" of vacuum at idle (950 rpms) and the driveability issues are minor and similar to a hotcam in a 350. I do run a vacuum can but don't think it's necessary.

It did run rich and had some cam surge after converter lockup at low speeds with a mail tune. So hands on tuning will probably be required to make it driveable.
 
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Discussion Starter · #5 ·
Thanks guys. I told him I thought he would need a vaccum canister, so start shopping. And I agree that a dyno tune will definately be in order. I wanted him to get one with the last engine combo. If not, then I guess it's time I buy a copy of tunercat and start playing.
 
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Discussion Starter · #7 ·
Originally posted by ÃÐïا§:
242/[email protected] on a 113+4 LSA? That's not THAT big if the rest of his combo can handle it. T56 or 4L60E? If 4L60E, what converter? What gears?
It's a 4L60E built by a local guy. It shifts too hard for me. He says he's going to a 3000 stall. He just installed 4:10 gears before the timing chain went.
 
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Discussion Starter · #8 ·
does he already have a converter? If not, I know somebody who wants to sell a Vigilante converter that would be perfect for that cam
 
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Discussion Starter · #9 ·
I'll ask, but I don't think he has one yet. I'll PM you for the details.

Edit: Cheston, your PM box is full. Shoot me one if you get a chance.
 
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