PRC 5.3 heads vs. LS6 heads

[Midnight02]

Hello All. I just got done reading up on a bunch of good threads from the search feature, however I thought I would post this in hopes I could get a little more insight into my specific setup.

It's time for heads. My own cost to benefit analysis has led me to choose between the PRC Stage 2.5 5.3 heads and the Stage 2.5 LS6 heads. Right now I'm making 390 rwhp and 388 rwtq with cam and bolt ons. My goal is to get closer to 430 rwhp from my daily driver (it isn't really a daily driver, however I would like for it to be as dependable as one). My only planned future mods are a 100 - 125 shot of N20 (still haven't decided between wet, dry or direct port) and a Moser 9" rear.

From the feedback and dyno numbers others have posted, both heads would be great for my setup. Therein lies the problem....how do I determine which is BEST? It looks like the LS6 heads have slightly better flow numbers, however the 5.3 heads might effectively raise compression more, hence creating more power without sacraficing low end torque. You guys have any thoughts as to which heads would work best for me? Finally, with your recommendation, can you please also let me know what your thoughts are regarding milling the heads as well.

[dkrowner]

go with the ls6 heads as its a better flowing head

[Midnight02]

Thanks dkrowner. Would the ported LS6 heads also result in increasing compression to around 11.75:1?

[dkrowner]

that just matters who u get them from couse gm sales ls6 cnc'd heads with 3 different compressions.i think its 62,65 or 66,72.then texas speed has afew of there own.lingenfelter
too,then patriot performance has some.are the PRC heads the texas speed ones?in if your looking
for the bump up in compression i think the 62cc cnc'd heads would work real nice.thats what i was looking into before i went with the turbos.hope that i helped in any way for u,and yes its a tad winded this post i wrote

[HB of CJ]

Ideally you mill should have major components that complement each other. Biggest mistake most make is to run too much cam or induction and the rest of the stuff must then play catch up without ever doing sooss.

How much cam and compression are you runnning? What kind and type of injection? Carb? Finally, the intended and actual use of the vehicle comes into play. Obviously, a daily driver differs from a drag car. Good luck.

[Marc 85Z28]

The additional compression that you gain from the 5.3s should nearly offset the few more CFM and better chamber that that LS6 heads provide. More compression makes bigger cams more tame. That and the 5.3s are hundreds cheaper.

[blackls1ta]

if its gonna be a street car and run 93 octane i wudnt go over 11 to 1,milling the heads will help compression, a 3 percent horsepower increase.

[blackls1ta]

Hello All. I just got done reading up on a bunch of good threads from the search feature, however I thought I would post this in hopes I could get a little more insight into my specific setup.

It's time for heads. My own cost to benefit analysis has led me to choose between the PRC Stage 2.5 5.3 heads and the Stage 2.5 LS6 heads. Right now I'm making 390 rwhp and 388 rwtq with cam and bolt ons. My goal is to get closer to 430 rwhp from my daily driver (it isn't really a daily driver, however I would like for it to be as dependable as one). My only planned future mods are a 100 - 125 shot of N20 (still haven't decided between wet, dry or direct port) and a Moser 9" rear.

From the feedback and dyno numbers others have posted, both heads would be great for my setup. Therein lies the problem....how do I determine which is BEST? It looks like the LS6 heads have slightly better flow numbers, however the 5.3 heads might effectively raise compression more, hence creating more power without sacraficing low end torque. You guys have any thoughts as to which heads would work best for me? Finally, with your recommendation, can you please also let me know what your thoughts are regarding milling the heads as well.

let me say this,since you already have the trick flow cam i wud recommend the trick flow 13.5 heads,they are matched to work together,your looking at 50 horsepower with the trick flows,they are worth the money ,you get what you pay for,good luck

[Marc 85Z28]

if its gonna be a street car and run 93 octane i wudnt go over 11 to 1,milling the heads will help compression, a 3 percent horsepower increase.

With a good tune on 93 octane you can run up to just shy of 12:1 safely. 12:1 or higher gets on the ragged edge. I'm currently running 11.7:1 without any detonation or knock retard.