Whatever a person who paid for a car wants to do with it is OK by me, as long as the steering and brakes work properly. Now some things I don't personnally agree with, such as molesting a solid, original survivor car. If the engine is burning oil or making rude noises, for sure repair it. If you find a fairly solid body without drivetrain, run what ya got or can get. Personally poking a 318 to 4" slugs is the hard way these days. Stroker kits are readily available for most any engine at reasonable cost, usually not much more than grinding the stock crank. Heads is similar, by the time you go through old heads and replace the guides, seats and valves you are real close to the cost of new aftermarket heads.