How much of a gain in hp would a 10.5 hotside be good for when on stock cams? And what about aftermarket cams? I'm thinking of maxing out the stock turbo now, then later down the line getting a turbo upgrade, so i was considering getting a 10.5 hotside as one of my next few mods. Thanks.

 

Dave Buschur did a writeup on exactly the info you are looking fer, please use the search button.

 

with cams you should see anywhere between 15-20whp. Expect most of the gains in the mid range to top end. It also has a slightly slower spool of 500rpm or so.