tonyb

I currently own 66cc AFR 205s with no milling stock out of the box.With a LS2 402 and flat top pistons w/2cc reliefs,what kind of compression and results in general will I be looking at.This is a street car with occasional trips to the track.All the supporting mods in sig would be swapped over.I would only be changing shortblocks and a decent camshaft change.Any recomedations would be appreciated.
Thanks
Anthony

lsx24

iTrader: (45)

That looks like a very good combo. I do know the stock compression ratio of the ls2 is 10.9, sorry I can't help with the other question.

muraoka

iTrader: (2)

i think 10.9-11.0 should be right. i have -6cc pistons and have 10.85 to 1.
matt

jrp

iTrader: (16)

your looking at near 12.0 CR with a .040 cometic and -.008 deck height. keep in mind 402 = 4" crank. longer crank = more SCR. you'll need a larger dish or larger chambered head to bring the compression down.

Brandon Boomhauer

iTrader: (10)

What is the typical deck height on a 402/408?

tonyb

12:1 would be good for me.I do little driving and with my experience with the 205s so far,there will be little detonation.Has anyone done this combo of 205s and a 402/408 yet? I would like to get some feedback on powerband and what kinda power I should be making and any kind of recommedations from there.
Anthony

Cary@Perf-Induction

iTrader: (1)

with such a small intake port cross sectional area, it will be a torque monster. a 225 cc head would make quite a bit more power without a loss of low end, granted you already have the cylinder heads, you may want to run a little more duration than you would normally see on a 346.

lsx24

iTrader: (45)

For such an application I would get worthwhile heads for sure..

Brandon Boomhauer

iTrader: (10)

Are you talking about running a set of 205s on a 402 with something into the 25x range?

I know the 24x range on a 40x ci motor is pretty tame..

lsx24

iTrader: (45)

Cool

GrannySShifting

iTrader: (10)

that head I think is just too small for a 400 inch motor tony. Definitely going to need to run some more cam, even a 230 duration cam Id keep the ICL 110 or higher and try and bleed off cylinder pressure, and try and feed that motor through the little head

lsx24

iTrader: (45)

Ok, if I was on with a choice of 205s or 225s per say for a 346 now, but planned on increasing displacement in the future (possibly a 383 a bit later), what heads would be wise to go with?