It's "not that big of a thing" when looking at a car built around the engine, it's probably more of a thing in a redo situation. Weight wise I'd say you'll still be in the 650-700# range. You'll need custom headers to clear things like steering, and then you may still need to change the routing on your column pieces. Firewall/floor issues are likely. And of course hood sides are either gone or will need a couple good size blisters. Your current radiator should be evaluated for capacity. But all these things can be done..........better to have been done at initial build, but hey...............this is hot rodding!