Sorry dude. I missed the post somehow, but I think we're all caught up in PMs.
Short version: I'd say that a 302 with a box R and stock motor mounts will fit under a 4" hood, but the hood will have to be clearanced on the side for the throttle body. With a 351, you need to mill the spacer to have a chance at clearing a 4" hood. Drop solid motor mounts would help, but I tried them on my motor and the Moroso pan wouldn't clear the k-member.
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