I have searched long and hard and haven't really found an answer.
I'm considering swapping my milled 799s for a set of prc 2.5 5.3 heads or prc 2.5 ls6 and what im trying to see is which one will be better for my setup right now. Currently my motor is stock bottom end lq4 with a 230/232 .598 .595 112+2 cam truck made 368 hp and best et was 13.96 at 101. my goal was to run 13s on 22s which i did but if i can go even lower with 22s i feel on drs/slicks it would be even quicker. any help appericated.

 

What converter do you have? The converter is a little too small for you based on how it runs. Strong MPH for a time that is only so so. If you hit 101 on 22's NA youre making decent power for sure.

The 243 is a much better starting point, however most 5.3 heads that have been worked also get larger valves which evens the playing field a little. The 5.3 head would give you more of a compression bump and would likely make the truck a little more feisty down low. Again, by the looks of it you kind of need that. That said, I would probably lean toward the LS6 heads simply because its a better head. Go to a slightly thinner gasket along with the smaller combustion chamber of the 243 and you will definitely see a major bump in power across the board.

 

converter is circle d 3200 hp series was thinking about upping to 34 or 3600 along with gears right now i have stock 3.73 gears

also all this is tied through a 80e

 

a friend of my (truckshop) had the 5.3 heads with i think the tr224 and made 400 through a 60e and 20s. in his old crew cab, also right now i still dont know my current cr. looking around on different forums some say 10.1 some say 10.5 i think the gaskets i have are .51 (shop)decided that i just told them mill heads and they suggest no more than .20

 

That 80e and gears are absolutely killing you I bet. My 2nd gear with 3.42s are close to your 1st gear. I agree with the converter being too small for your setup. It would help more than anything because hp is not your problem, great mph. Torque multiplication is.

 

On an LQ4 stock bottom end.

With a 64CC your at 10:1-1 compression ratio

With a 61CC your at 10:5-1 compression ratio

60CC is showing 10:6-1

The flow numbers are identical between the 2 heads. Looks like another 10cc at .600 lift on the LS6 castings.

Might as well get the LS6 castings with a 60CC.

I would go with a 3600 stall too.

 

forgot to mention i have 3.73s

 

A set of 4.30's will wake it up a bunch. I went from 3.73's to 4.10's and it made a big difference but I wish I had gone deeper. The buddy that bought the truck from me did go to 4.56's and holy cow! It flat screams now!

 

Sorry not to jack the thread, but if the Valves and valve sizes are the same along with the CNC port job, how is the LS6 243 style better than the 4.8/5.3 862? Pretend the combustion chambers are the same size for this question.

This is a serious question not trying to start a argument or anything like that. Thanks.

 

The port design is different between the 2 heads.