PRC 5.3 2.5 Heads on a 402?
#1
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I posted this in the LS1-LS6 section but did not get much response so I thought maybe it should go here, vendor input will b e greately appreciated also:
Currently have H/C on my 346 and was wondering if I can reuse PRC 2.5 heads with a 402 or will they be too small. Valves are 2.04 and 1.575. Currently putting out enough power with a 233 239 600 605 on 112 LSA (and other supporting mods) to be able to take a new stock C6 Z06. Now if the new Z has anything like a tune or headers they pull on me slightly so its time for the 402. So again question is will I leave any power on the table if I use the PRC heads or can they support a large cam for the 402 with supporting mods?
Thanks,
Mark
Currently have H/C on my 346 and was wondering if I can reuse PRC 2.5 heads with a 402 or will they be too small. Valves are 2.04 and 1.575. Currently putting out enough power with a 233 239 600 605 on 112 LSA (and other supporting mods) to be able to take a new stock C6 Z06. Now if the new Z has anything like a tune or headers they pull on me slightly so its time for the 402. So again question is will I leave any power on the table if I use the PRC heads or can they support a large cam for the 402 with supporting mods?
Thanks,
Mark
#2
TECH Apprentice
iTrader: (24)
Join Date: Nov 2002
Location: spring, TX
Posts: 350
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Just FYI, I used a set of Absolute Speed 5.3L Stage 2.5's with 2.04/1.575 valves on my 402 with full bolt ons and Fast 90/90 . With a 244/244 .612/.612 112 through 4.10's, I made 47x RWHP.
I'm currently in the processof a L92 Swap, so I'll Post the difference in numbers when it's complete.
I'm currently in the processof a L92 Swap, so I'll Post the difference in numbers when it's complete.
#5
TECH Apprentice
iTrader: (24)
Join Date: Nov 2002
Location: spring, TX
Posts: 350
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech20year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
YOu really need to look at the flow numbers on that head and compare that to the lift on the cam you want to use. If they peak lower or don't peak as high as a cam you'd want to use on the 402, you would be leaving some on the table. In my case, the heads were set up to peak at around .550 lift and peaked out @ around 310 cfm so I felt I would gain more with the L92 swap. Hope that helps....
#6
TECH Fanatic
iTrader: (2)
Join Date: Nov 2006
Location: Aztec, NM
Posts: 1,360
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
They are no doubt a good cylinder head, but I think that a set of AFR225's,Trick Flow 225's, or a set of ET Perfomance 225's would make you more RWHP over your TSP heads. I will have more info on the ET Performance 225's & a 402 very soon. Right now I am predicting between 575-590 RWHP with this current set up on my cousin's 99' 'Vette'. With this same set of heads on a 93,000 mile stock short block 346 he was making a little over 500 rwhp(aggresive launches=BOOM). This is his daily driver car that ran great in rush hour traffic(I credit this to haveing an excellent tuner).
#7
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
This is all very helpfull and I may try the PRC's with the 402 as I was making north of 480 hp to the rear on the 346 setup and the heads do seem to flow well, but keep the comments comming. Worst comes to worst I can always swap out the heads at a later date if hp/tq is short. Still havent desided though so if anyone has any other comments opinions please don't hesitate.
Thanks
Mark
Thanks
Mark