We built a couple of Caterham type cars. One was a stainless steel Robin Hood kit with a 2 litre pinto engine. The other had a 3 litre Ford V6 and a Dutton. Good for short runs but actually crap to use. The 3 litre was exceptionally fast in a half ton body.
I would be looking for something like an Austin A40 like the one i toured all around Britain in back in 1976. 1100 engine and removed the metal cooling fan to gain a few more HP. Quite a fast little car for a 1960 model.
I liked my 2 stroke SAAB and 61 Sunbeam Rapier convertible but best fun was the 65 Mini Cooper and with its wide wheels , it could knock wheel bearings out every 3000 miles and return 24 mpg