Stroker87

I have a pair of 243 heads at the machine shop being checked out i got some info today about them, what bothered me is that stock 243 (non ls6) from what i read has a 64.45cc chamber, The machine shop checked them and they are 65.5cc chambers?

the heads have been ported here is what info I got on my heads

65.5cc chambers
215cc intake
77.5cc exhaust

this is what I read online for stock untouched 243 heads
64.45cc chambers
210cc intake
75cc exhaust

I'm worried compression will be lower since there is 1 point difference? this is a daily driven street car, can or should I bump compression to 11.1? for a daily driver is 11.1 ok? "if" I do bump the compression will i need to change push rod length?

list of mods 03 c5z
224/230 .581 .592 114 lsa cam
ported fast 92 / ls2 tb
kooks long tubes & gutted x pipe
monster stage 2 clutch
rpm lv5 m12
c6 diff upgrade & 3.73
B&B exhaust
of course dyno tune
tick adj master

I guess i'm really just trying to see "if" these heads are going to give me any Hp gain and should I mill them or is it opening up a can of worms?

C5 Pete

I can see no reason not to mill those heads provided you have decent pump gas available.

11:1 is the lowest compression I would run. Why not go to 11.5:1? A good tune and good gas and you'll be fine.

You should measure pushrod length regardless of what you do to the heads.

Have fun with your project.

Sigforty

I have had two sets of heads on my car killed to 58 cc. You may need shorted pushrods or you could possibly shim the rockers instead. With a cam the bump in compression is worth a few hp.

ZZ06

Like mentioned, good gas and tune. 11:1 is fine to run on the street. My 418 is 11.3:1.