I dont think a turbo that works effeciently on a stock 4.8 will feed a forged 370 too well at the boost levels most would run on a forged motor. A turbo sized for the 370 would probably leave you with a pretty annoying lag on that 4.8. Just my .02

 

I ran a t67 on a 370 at 12 psi. Went 11.35 at 118. Is it perfect? No. Did it work? Much better than expected. Could have used a bigger turbo at the track, but on the street it worked fantastic.
With the right stall or a quick spool valve a larger turbo would work great on a smaller engine.

 

Don't tell foose04 a 76 is to much for a 4.8! LOL
Just contact kyle at KBRacing and let him get you boosting, I just did and he is great to work with and his kit has proven its faster than most of us can afford to feed!