I would think that with a good 3500 stall, cam, and tuning that the procharger would be quite a bit quicker. Black Blown would definately know better than I though. He currently has a Procharger. He's a good one to go to with questions.
If you are already planning on having to do a few more things then go with a centrifugal is that is what you'd prefer. Dont forget larger injectors. Those will be an absolute necessity to make that kind of power. Those add another $450.
425rwhp with a 4.8 isnt going to be easy. If that is your goal I think you are in for a big surprise. F8L has an STS on his 5.3 with cam and Meth and is putting down only a little more on 13# of boost.

 

The ATI has a good top end, but say you're in a highway roll race ATI vs Radix....70mph, you both shift to 3rd gear. Rpm's drop to 3500. Radix is making 8psi at 3500, ATI is making 3psi at 3500. Who's going to walk away?

I have the ATI, and the only way to make it perform well from a stop and at the bottom of gears is a big stall. I have the SS3800 and rpm's only drop to 5000 at the shift. The tradeoff is driveability. It's a little loose.

 

I'm kinda basing that on looking over peoples EFI logs with the radix and comparing them to mine. Mostly the MAF numbers at the top and bottom of a shift. At the bottom of a gear say, 3500-4000rpm the radix is at 300 flywheel horsepower, and the ATI is at 200. It takes a stall with 5000 rpm shift extension to see that number at the bottom of the shift with the ATI.(these are ballpark numbers for the sake of comparison, 8psi)

With a larger cam, you probably could be faster. A small cam, its gonna be close.

 

Well Maybe My Best Bet Then Is To Just Save Up A Bit More Pennys And Go With The Radix.a Cam Stall Gears Wit Any Of Them Would Be Bad ***,so I,m Not Going To Keep Draging This Post Out. Thanks For The Help.does Any One Know If They Will Finance A Radix.[prolly Not]

 

Good point. Didnt think of it that way. Like I said, Black Blown 02 is the man

 

Guess I should also state the other side of the argument also.

Say you want to run 13psi with the ATI with a big stall. Versus Maxing out the Radix (lets say 11psi--Seems to max at around 450rwhp)

ATI-- launch (4000rpm) 8psi, top of shift 13 psi, bottom of shift (5000rpm shift extension) 11psi.

Radix--11psi straight through.

I think the ATI would have the radix covered in this scenario.

Just depends how far you want to take it.

For lower boost daily driver levels I say Radix all the way.

 

Not sure about radix max boost maybe It'll go higher than 11psi, but I do know the compressor maxes out at around 450rwhp.