rkjp

So I've done some research and decided that a Comp 265 or 275 is the cam I'm going to go with. Both have decent power from down low and rev to 6700ish.
I have a '02 Firebird block with heads.
I'm going to be looking for a LS6 intake.
The question is, I have a '02 5.3 that I'm using as a interim motor, would the heads off that be better to use because of the smaller chambers? From the research I did it looks like the valves are the same size. Obviously they would get some porting. Anyone have some good pics of how they did theirs?

This is what it's going into. It could stand to loose a little power down low in the name of higher HP.

NemeSS

iTrader: (127)

old 706 5.3 castings are equipped with 1.89 intake valves and 1.55 ex.
if the 5.3 heads are 243 or 799 heads, then they are ls2 heads and way better than 5.7 ls1

rkjp

It's an LM7 5.3. Either 678 or 862, depending on what number we're talking about.

NemeSS

iTrader: (127)

old style low flow heads, they have smaller int. valves than 5.7 flow less and chamber is smaller by 5-6cc. will need valve upgrade, vj and machining just to bring up to ls1 level.
make more sense to find 243/799 heads.
and spend money porting or upgrading those. although stock 243/799 will support over 500bhp with correctly matched and supporting components.

rkjp

The key is to keep it somewhat cheap. With what I do to them, engines only last 2 years.
Anyone have and 243/700 castings for a reasonable price?

NemeSS

iTrader: (127)

yup!
pm sent