TT 5.7 hemi in 75 duster

If you go with a cummins turbo you would want them off of the mechanical trucks, the HX35's are what the ford guys run on the 2.3l engines. But I think those might be too small for your app. Ideally i would say look for two turbos off of GN's or T-types. Not much else from a stock app is going to be big enough.
What is ur ultimate goal stroker and big boost? 25-30psi with a built engine is good for well over 1000hp if it's built right. What trans are you putting behind the motor?
This doesn't say what was done to the engine or how much PSI but gives you an idea.
http://www.plumfloored.com/vortech_charger.htm