nonnieselman

iTrader: (10)

hey guys,
We are putting together a 385ci LQ9 Iron Block, L92 heads, L76 Intake, LS2 rotating assembly with Forged pistons that are flycut.

The current cam sittin in the box is a 218/220? im not exactly sure yet.
But what cam would you guys recommend?

This is goin in a 99 Trans Am, its already got a Yank SS3600.. and 2.73 gear


Im not good with picking cams and such. Just wanted to see what you guys thought.

Ill get the specs on the currrent cam this afternoon.

Thanks!

SynergyV8

iTrader: (1)

Those 2.73's call for a little less cam...The Comp XER273 is a good start, especially in a truck. You're going to want to mill those heads or aim for a target compression of ~10.7. I'd hesitate to take any more than .030" off the heads so wherever that leaves you with compression...that will work fine.

If it were my grind I'd look somewhere around a 226/230 on XER lobes for .580-.600 lift to take advantage of the breathing capability. Try XER lobe #3723 on the intake side and XER lobe #3725 on the exhaust side ground on a 112 with 2 degrees of advance.

1quickRST

iTrader: (2)

If you are really having trouble finding a cam I would suggest calling comp cams and talking to one of their techs. They helped me with my cam and I am very pleased with the results!

nonnieselman

iTrader: (10)

Ok, the CR is suppose to be ~10.6 with the stock head gasket. the L92s have a touch of work done to them.. along with 918 blue strip springs.

Thanks for your advice.
that's a better answer than what we got from the Tech side.

any more advice would be appreciated.

old motorhead

iTrader: (10)

I had a couple different cams in an LS3 vette. Vette had all the usual bolt ons, manual tranny, and 4.10 gears. Comp cams XER281 specs out at 232/234 with about .600 lift on a 112 LSA. It looks similar to the TX speed torquer II. It made about 460 hp and 442 tq. It had some low speed issues that the wife didn't like. Pulled it in favor of a 226/234 with .615 lift on a 114LSA. It made a few more HP and lost about 30lbs of tq vs the Xer281. More wife friendly cam though.

SynergyV8

iTrader: (1)

By the way, how are you making 385ci? I wasn't aware the LQ9 blocks could be bored out that far.

nonnieselman

iTrader: (10)

That's just what I was told it was.. its a 4.065 bore? LS2 crank and Rods. I don't know how to do all the calculations.
maybe its a 370ci?

got another issue, we have Aeromative fuel rails. would like to go with a factory rail setup?
but I think it might be more simple to just get a regulator and put the fittings in...

just tryin to get everything ready and bolted on before the install.

thanks guys!

SynergyV8

iTrader: (1)

376ci 6.16L.

With an adjustable fuel pressure regulator you'll be able to fine tune later on.

nonnieselman

iTrader: (10)

Very true.. didn't think about the easier tunablility.

does different pistons change the CI?
they are flat top with 2 valve reliefs. or is the CI calculated just by stroke x bore x 8?

if we use the Aeromative rails we have to make some mounts to secure them. so we have some fab work ahead of is..

SynergyV8

iTrader: (1)

I'm not 100% sure I understand your question...

If you're asking if displacement is affected by the type of piston (dished vs flat top vs domed for example) then the answer is no. If you're asking if displacement is affected by the size of the actual piston bore, you bet!

Displacement is calculated by adding all the volumes of the cylinders within an engine.

Why Aeromative rails in the first place? Did the stock ones not work in this application?