Well, I'm getting the PRC 2.5, 5.3 heads amd installing a built tranny with a YANK Extreme 3600 stall.
What rwhp should I see over my old setup. I'm hoping for 400 rwhp

 

380 or so unlocked. The converter will eat probably 20rwhp. But 400rwhp isn't a bad guess with those mods. The PRC's are good for about 40rwhp.

 

Your numbers should be close to mine:
https://ls1tech.com/forums/dynamometer-results-comparisons/335231-a4-3500-stall-12-bolt-w-prc-heads-230-232-cam.html

Before the heads mine made 365 rwhp unlocked. After the heads it made 402 rwhp & 419 rwtq unlocked and 430/391 locked.

I have the same heads, a little more cam & crank pulley, but also have a 12 bolt, very inefficient converter & midlength headers... Since you have true longtubes & less drivetrain loss from the stock 10 bolt your numbers should be pretty close. I'll guess 390-400 rwhp unlocked.

 

Yeah, I did my 362 rwhp with a shot tranny and some say an extra 10 to 15 rwhp if the old tranny was good.

 

My tranny was also shot on the 402/419 pull. It went out completely a week later. I'm saving for an FLP level 4 now.

 

Is your car Silver?

 

Nah, its red.