Another option for a little more “yank” is a 2.8 or 3.0L GM V6 from an S-10 pick-up or a Generation III Camaro. These are “longitudinal” (Rear Wheel Drive)and are small enough due to their 60 degree configuration to fit.
These are also easier to find than the Ford 60 degree 2.8L V6’s and the GM V6 has a vibrant “aftermarket” for hop-ups. You won’t need a computer either. Edelbrock makes an intake for using a carburetor.
Another choice is a Toyota 2.0L four (C20). These were very common in RWD Celica’s and their trucks. Keep in mind that you want to buy your engine and trans from a REAR WHEEL DRIVE donor. These engines are also popular and have aftermarket stuff available for them to.
I started to build a CMC Ford based TD kit that was powered by a Buick 3.8L V6 and had a TH200R4 over drive automatic trans. It was also getting an 8″ Ford posi rear with 3.55 gears. This car would have been comparable to a small block Cobra…maybe faster?
However, I sold the car as a “roller” to a guy in Sacramento, CA (I live in NJ). He wanted the stock Pinto 2.3L “Lima” and the stock Pinto 3 speed automatic trans. I’m not sure if he ever finished the car.
The Buick 3.8L V6 ended up in a restored SCCA spec racer after I sold it. The TH200R4 OD trans is behind a “worked” 4.3L Chevy V6 in my 40 Ford Sedan. It has the 8″ Ford 3.55 posi rear in it too.
If I ever hit the lottery, my current British Coach Works (Chevette) MGTD will get a V6/automatic set up. I’ve also been toying with the idea of the Toyota or Miata 4 cylinder set ups with a 5 speed manual and turning it into a “Vintage” racer. The Chevette drivetrain just doesn’t cut it.