1quickTransAm

iTrader: (4)

I am currently building a 383 LT1 with 6" rods and AI200cc heads, and it has a 150 shot as well. I am having a shop with a good LT1 tuner do the machine work, spec the cam, and later dyno tune. From our talks today we ended up with 230/236, 114 LSA, .576/.571 as the specs. I rarely go to the drag strip, but go about once a year and will also do 1 or 2 road race track days. The car is mostly just a street toy and I want it to be a lot of fun to drive with a power band that pulls through the RPM range with a high RPM bias (street tires...). I also don't want a lot of lope at idle.

Based on this, what are your thoughts on the 230/236, 114 LSA, .576/.571 cam? I notice neither LE or AI have cams in this size with so much lobe separation. I guess I am hoping for a last minute gut check. Thanks!

bowtienut

iTrader: (1)

There's a reason AI and LE don't advertise cams with that much duration and wide lobe separation. For other than forced induction, the early exhaust opening and late intake closing sacrifice power.
It won't make your engine a "dog". If you value a smooth idle over horsepower, then have at it.
Those lobes on a 110 separation would still make a VERY mild-mannered 383.

1quickTransAm

iTrader: (4)

Wouldn't a wide LSA have the exhaust close sooner relative to intake opening?

Edit: Nevermind I reread what you wrote and I was thinking the same thing.

HellTeeOne

Tighten the LSA to 110 or so.

No need to do a "nitrous cam" unless you're running a 300+ hp shot.

Talk to AI about their 234/242, .614/.599 grind on a 110, I'd probably do something like that if I were building a street/strip 383 with those heads.

bowtienut

iTrader: (1)

All true.
That's the exact cam we picked for my bud's 4600 lb ImpalaSS. LOTS of grunt, runs low 12's with a 3400 converter, 4.10 gears, and knocks down 18 mpg cruising at 70-75. He also has the AI 200cc heads.

And yes, a 150 shot does not warrant any variation whatsoever in cam specs from what you would pick for best NA power. My 108 LSA cam picks up 120 hp on a NX 100 shot.

bufmatmuslepants

iTrader: (3)

I got my cam from fex77k, who had it in his tube chassis 67, its on a 107.5 and he said the tight LSA caused no increase in power over a 100 shot, have you noticed anything the same on your 108? Or have you not ventured over that 100 shot? Im just curious, no nitrous for me.

bowtienut

iTrader: (1)

hvyss runs the same cam as mine in his 385 LT1. It swallows a 225 shot just fine and runs 9.90's at 4100+ lbs. He's running the same AI200cc heads too.
If fex saw no improvement over a 100 shot, he had something else going on such as restricted exhaust ports/flow. Or.....maybe it's just some weird grind cam that I'm not taking into account..?
But no, just because it's on a 107.5 LSA wouldn't make it unsuitable for a ~200 shot.
I'm not venturing over a 100 shot on my rebuilt stock bottom because I already consider myself on thin ice producing about 660 hp at the crank as is.

bufmatmuslepants

iTrader: (3)

The cam was too small for his goals anyways and upgraded, haven't heard from him to know what he went with. He did have only dart 180s on it, could have been more of the problem.

bowtienut

iTrader: (1)

Yes, I would agree with that.