PRC 5.3 heads + FAST 92 combo dyno

**Midnight02** · 05-14-2008, 08:18 AM

Hello all,

Just got my car back from the shop after installing a set of PRC Stage 2.5 5.3L heads (milled to 60 cc.) and a Vengeance ported FAST 92mm intake and Billett 90 mm CNC throttle body. See my sig below...I have a bunch of bolt ons and a mild cam. Before the install I made 390 rwhp and 386 (I think) rwtq. After the install, it made 435 rwhp and 406 rwtq...a gain of 45 and 20 respectively.

While the power gains were nice, the biggest difference can be felt down low. The car now makes over 350 rwtq at 2,700 rpm (which is pretty much where the dyno graph starts). Driving around on the streets just became a LOT more fun!

**SSwt00SS** · 05-14-2008, 02:43 PM

stout numbers no doubt. im running a 224/224 .581/.581 @112, ported 90/90, Ls6 Stage II heads, 59cc, full exhaust and laying down 443/402...

what made you decide to run 5.3 heads? no doubt you feel the difference, esp with some 3.90's. now, what does she make on the bottle...?

**Midnight02** · 05-15-2008, 12:20 PM

I went with the 5.3 heads from PRC based primarily on the fact that they had a proven proven track record and I waas looking for a budget head. The increase in compression was exactly what I was looking for (11.0:1) and I knew that would work well with my setup and I was confident the heads would help me out down low. The car still pulls strong up top and it probably has a few HP left in it because the cutout was completely closed during the run and I have a Flowmaster catback (which is probably only hurting me for a few HP).

The bottle is always a nice addition to a good N/A setup. I went with an adjustable dry plate kit and will probably get comfortable with a 100 - 125 rwhp shot. I might step it up to 150 and pop it on the dyno just to see what that looks like! It would be pretty sweet to go knocking on the door of 600 rwhp (although I'm cheating with a bottle)!

I like your setup a lot and I'm sure it feels awesome on the streets! I fought with my decision between the 5.3 and the LS6 heads for a while and honestly didn't know which way to go. I figured the LS6 heads would probably flow a little better up top, however I just wasn't able to find enough information about them to get comfortable. At the end of the day, I figured there would likely only be a few HP difference between the two, so I went with the cheaper option (the Stage 2.5 5.3's without springs were $1,032. shipped)