TBJ, the cost isn't too big of a deal. I just want a well-sorted engine and after doing research, settling with a .12 is sounding like a better idea.

If you would, please explain the difference between the following:

O.S. 12TZ (P)-T 3-Port Turbo

O.S. 12TZ (P)-T 5-Port Turbo

O.S. 12TZ Turbo

O.S. 12TG w/12E Rotary Carb

Associated LRP Z.12R Team Spec

Safe to assume the 5-port isn't race legal?

Also, no complications with mounting one of the .12 engines, right?

Thanks,

Freddie