I think you would be fine with the 61, the 66 might be a little low.
This would also depend on the turbine wheel that you get.
In the next month or so I will get between a 61-67MM unit on my junk.
As long as it isn't a re-stalled D5, you should be more than fine.
I used a ball bearing 61 from Cotton 4" inlet, 2.5" discharge matched with a PTS 9x11 converter with an advertised stall of 3000. It spooled stupidly quick. The 66 you would probably need a 3200 at the very least.
I will post back tomorrow with how my CPT66 BB spools with my new Art Carr 9" ( 3400-3600 ). Car is at the tranny shop til then. I hope its not too much stall.
Bryan
Ran a Pats 3000 on my car(lotta work done to motor and heads, etc) with a CPT66BB, it spooled nicely on the street.. Switched over to a "O" pump 5 disc Vigilante and cant use street tires anymore
70 Q-trim dude. It's all I ever used...... Must have me confused with someone else..... Unless you can dig up an old post? I don't think I ever said that. Prove me wrong.......
just bought a 66bb from cotton 3" inlet 2" outlet waiting for new pts radiator and eric burned me a new chip to match everything running a 3200 stall should work really well i think can't wait ,