I have a 77 F250 that has a 400 in it. Well the 400 is shot and I may have a chance at an already built 460. Will I have to change the frame perches or are the motor mount points the same between these 2 ?

 

Buy a set of L and L swap mounts. That's the easiest option. No, you don't have to change out the towers, just the motor mounts.

 

I personally think the L and L ones suck (way too wimpy) go with blackbird's setup and you will never have a problem not to mention it takes the stock 1990's motor mounts.I've torn the L an L's in half inside of 5000 miles without even trying. (with an automatic)