A little Turbo Selection Help

When I did my turbo setup, I used a modified Corvair (Rajay) turbo. 500 Holley 2bbl (draw thru), on a 170 engine. Don't know the HP, but car weighed about 2700 lbs, and ran 13.4's at 104 mph, Was at 10-12 lbs boost. Boost gauge needle would vibrate pretty bad. The mod to the turbo was just the compressor housing, to convert from the small Corvair 1 bbl 3 bolt inlet to the now common 3 inch inlet.
PS: I did have a homemade water/alcohol injection system that turned on at 5 psi.