Like Steve and Kurt, I also ran a 351 C in our 68 Mustang bracket car. Great engine and it responded very well to modifications. Only question I would have is will it fit between the shock towers in the 63? I know in the 67 up cars it will go, but the earlier ones are a little tighter in that dimension. They are a little wider than the 351 W, and certainly wider than the 302's.

Don