Listen to Tony.
It's horsepower (per pound) that's important, especialy for a lightweight fiberglass car.
The 270/302s were the best in the 50/60s for 3,000# coupes/sedeans where the higher torque was a factor on the 1/4 mile Drag Strip.
The 250/292 will rev to 7,000+ as they have 7 mains. The 292 is 50# heaver & might be to tall for a roadster however.
Good luck
