No body lift, a 351 and some types of extreme motor mounts. Plus if the engine is tilted even slightly more than normal I think you have your answer.
Another tell with a 302 would be how much clearance you have between the lower idler pulley on the passenger side and the top of the crossmember. With a 351 I don't know how much that relationship changes, but let us know what your gap is there and whether you have the large idler or the small idler.
Whether you like them or not, I see a 1" body lift in your future. It's certainly the lesser of two evils between lifting or cutting.
Are you going to run a carburetor, or is this a Ford EFI setup?
If EFI you might benefit from a body lift anyway.
Paul