the patriot heads i have are the 5.3L stage 2 heads with 63cc chambers, what would the compression then be on my ls2 if i were to use these? could I still run on 91-93 octane premium fuel or would i be getting into the race fuel only area?

what are the benifits of running these stage 2 heads over my oem ls2 heads?

i plan on running a cam with a .570 lift with my stock rocker arms.. and i want to leave the bottom end stock. I also will be getting my ls2 intake and throttle body ported.. also will have long tube headers and dual 3" exhaust with a cold air intake system..

anyone see a issue with this setup? im mostly worried about the patriot heads on the ls2 if its any good or not? im guessing so since there ported and 2.02 1.57 valves and can hold a large cam. but still not sure..

You guys have ideas??

 

You'll raise the compression slightly.
Stock LS2 heads are 64cc chamber for a 4.00" bore and give the motor a 11:1 compression ratio.
The 5.3 heads are 63cc chamber for a 3.78" bore so 11.25:1 or 11.50:1 at most with stock gaskets.
You could use a thicker gasket to lower the compression back to 11:1.

The stock LS2 heads flow around 260cfm at .600" of lift and the ported 5.3's show around 300cfm at .600" of lift with decent mid lift numbers. Its not a super super upgrade but its a damn good one for the price the Patriot 5.3's go for (and the dual springs are going to be over kill for your cam).

92 or 93 octane shouldn't be a problem as long as you tune it correctly.

 

now thats the kind of answer that im looking for! thank you..

so it seems as tho given a decent cam with those patriot heads and a ported ls2 intake n tb, that should net 450ish whp with suporting mods such as lt headers and exhaust and cold air intake.. or would it be even more power yet?

 

Somewhere between 430 to 450rwhp with the patriots and 23x/23x cam, headers, ported manifold, and all the trimmings.

I'm at 410rwhp/400rwtq through the GTO with 222/228 cam, headers, cat's, non-ported manifold, and an under drive pulley. The Patriot 5.3's and LS6 stage 2 both flow about the same.
Dyno Sheet http://farm1.static.flickr.com/148/4...da76b747_o.jpg

It varies as to what one will see, and it will also depend on the dyno you put it on. Also is this an Auto or a manual?

 

its a manual. and sorry i changed my sn, my old ones password i forgot and my cpu had to be restarted haha

 

I also, and thinking that maybe running those 5.3;s i have is overkill for my goals. i like how yours is 410whp and 400lbs, thats about the exact power im going for for my setup. lol if ya dont mind I may copy your setup just run with no cats since i have no co2 police in iowa