Thinking out loud, spitballing...
The engine (1990 2.3) was built for salt lakes racing in a ranger using mechanical fuel injection. I suspect upper rpm would be in the 8,000 or higher range. I also have a 2bbl carb and efi (welded shut holes) manifold I could use, which would probably be easier driving on the street.
I have an 8.8" with 3.73, 4.10, or 5.13 ratios to pick from.
-I have the original 3speed automatic that came with the car. Probably a c3.
-I have an m5od behind a 2.3 in a 93 ranger.
I don't have money to rebuild the c3 but maybe it's good enough for now. Only way to know is use it.
Or, I adapt the m5od into the pinto, along with the hydraulic clutch system. I'm not too sure how hard that would be, I haven't done anything like that before. Tho I think I have the tools and tenacity to accomplish it.
But perhaps there is an easier, better, still somewhat cheap alternative standard or automatic that I don't know about...
Anyone have ideas?