which head would be better? The 5.3 or the LS6 head? 99 LS1 with the MS4 cam with all the supporting valve train, 90 fast, 90 throttle body, little to no exhaust and a 150 wet shot with c16. I have the lingenfelter two step so i can take time out.I have heard that the 5.3 would be killer for what i have, but i am worried about the runner sizes. are they smaller that the LS1 head, or comparable?or would the LS6 head be better?

 

your engine will need to breath with that cam, i would go with the ls6 243 heads. the 5.3's will work but the cc's are smaller and will not flow as good as the ls6. the 5.3's will raise your compression ratio for more hp. i believe the ls6 is better from low rpm to high rpm. if you port the 5.3's then they will be better. or just as good...

 

thanks.. so that means its time for new injectors..damn, the list never ends... would anyone happen to know just out of curiosity if the runners are the same size for the 5.3 as the stock LS1 head??

 

What pistons are in your car currently? that determines a whole lot because p/v can become a issue if you go with bigger valves. If your using a stock pistons I'd defiantely look to the PRC 215 head. We've seen 50+rwhp gains with them while trying to maintain good p.v.

Bigger valve stock LS heads will just not clear properly on a stock piston with the MS4 camshaft

http://www.texas-speed.com/shop/item...d=993&catid=20

 

Use your ls6 heads and have them bowl blended and back cut the valves, that will wake it up extremly well and they will flow like a mo fo! Chances are you will need injectors probably around #37 range........ I'm haveing to do the same thing with my cam and head set up