I would look around online. There are some killer deals on new units. I was looking for one for another project and I found one capable of 7-800hp on a 300" engine for $900 brand new with the T3(IIRC) inlet. So it was easy to find a flange to mate to it. You can also look for used import stuff but I dont like used aftermarket turbos unless i know the guy I'm buying it from.