Made up my mind about more HP, now a ?

Small block is the way to go if you dont want to go through the pain of cutting up your car. A big block will be a tough deal to fit without cutting the fenderwells for headers etc. The stroked 318 might be my choice. Depends on whats inside it, comp ratio, cam, heads rods etc. If its stuffed with upgraded parts then why not ? Make sure its got the engine mounts that will work with your car, in the event that its a later 318 -ie magnum or something like that. I think they changed the mount system on the later engines for trucks sometime in the last years of the 318 motor.

Keep in mind that the 273 exh manifolds for these cars are pretty restrictive, you'd be much better off using the shorty headers from spitfire.