would there be any advantages for me to swap stock 5.7 heads with my 5.3L heads
It should drop my compression I think ?
any other advantages to swapping them?
My list of mods are below
running 9#'s of boost now what would it be after a head swap?

jim
<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

 

prety sure the 6.0 heads will drop your compresion more and they flow beter than the 5.3 or the 5.7

i think you will loose some power with the lower compresion anytime you are not under boost. when does the boost start to come on? do you see much boost under normal driving?

 

IMO, running those heads will, of course, allow you to run more boost, in return, that will give you more power.
Most of the buick guys would rather run way more boost than higher compression. I think what i'm trying to say is, more boost makes a lot more power than compression.

i would do it, i'm thinking about 6.0L heads on my ls1 and a turbo, i would hate to run like 4lbs of boost on my ls1 and not be able to go much more because of breakage.

this may generat some debate, compression vs. boost, but i think the more boost you run, the better.


later,

allen

 

i agree, more boost, less compresion = more power

but at what cost, if he doesn't see any boost till 3500rpm most of the time he will be down on power but in a drag race he will be faster.

now for the hard question, what compresion ratio should he shoot for. even more important(to me) what ratio should i shoot for?

 

on boosted motors i was told like 8.5-9.0 is good and 9.0 would like be the most which is what i am going to run. but i also say a discussion in the forced induction forum about running high compression with boost. but as you said you would not get as much power. just my .02$

 

I would definitely run the 5.7 heads. The bore isn't too large of a difference to hurt and you will drop your compression. PLus you will gain a larger intake valve. When I had my whipple, I had a set of 5.7 heads waiting to go on if I decided to keep the SC. I sold the heads after I pulled the whipple off.

FWIW - The same amount of boost on a lower compression motor will be "better" boost. Meaning you will get more power out of 7 PSI with a 9:1 compression than 7 PSI on 9.5:1.

 

See the way i see, it is that when i do put the 5.7 heads i'll then in turn put my smaller pulley on. The smaller pulley should give me an additional 2-3 Psi.
This in fact should also start to build boost quicker instead of seeing 2Psi at 3000 rpm i hope to see maybe 3-4 psi maybe. Who know this is all a big experiment, when it comes down to, the Procharger and the 5.3 are still new water and unexplored .Coupled with better flow I'm hoping to have a gain over the entire rpm reange,rather than just at the top of it.
I want it to be a little less Spikey on the street as that's where i do most of my driving.

jim

 

Glad to see ya back Jim. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

I don't think there is any downside to putting the 5.7L heads on. Are you going to have any porting done to them before they go on?

You might see 1-2psi less boost after the swap. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

John