I think, if the car is in need of a restoration, the place to start is not the engine. I always found it strange that we all want more power and faster - but then don't have enough money for body and paint work. I know for me personally I made that mistake on pretty much every car i did until I was in my 30s. Get the body solid and waterproof, and the car mechanically sound in terms of suspension, brakes, rear axle, etc, then think about an engine.