I'd stay with the pinto... keep it nice and original. you have the gearbox so and engine there so I wouldn't waste money and time finding a new engine. Put a nice set of carbs on her, an exhaust and a cam and you'll have loads of fun.

If you do decide to go with a new engine keep it in the ford family...

Just my 2 cents hope it helps

well i stuck with the pinto, keep things on the cheap side and stay true to ford.
got my cam ground and new brakes, it now goes really well.
now i get stuck into the body...

If your adventurous and can't afford webers. Check out a megasquirt ecu. I run quad 38mm gsxr tb's, commodore coils, falcon vr sensor. Cost about $1k to build fuel and spark + 1 hr dyno time to tune it