I appreciate the guidence since this is new territory for me. I have built many V8s (mostly Pontiac and SBC, and usually went naturally aspirated with nitrous. I now find myself wanting something I have never done before; hence the turbo straight six.
So an old Chrysler turbo may work, since that's a T3. I know the one Volvo turbo I was looking at was a T34 and a Conquest (which my buddy has one which no longer runs) has a T42 (or at least this one does, may be an upgrade 'cause I think I remember them having a T3 based turbo originally).
So I just need to figure out the compressor size and the ratio for any of theese and see if it is inline with the specs you are giving me.
Like I said before I am pretty much experimenting at this point and if I get onto something I can go further later since too much HP now is going to blow my drivetrain apart.
I will save the T72 I have laying around for later.

Do you have any ideas on where I could find VE numbers for the Chevy 250 so I can calculate the plenum area I will need?