Let me be the first to say NO NO NO about the Mustang IIs being built on the same platform. Some of the stuff is the same, but most of it isn't. Same front suspension, same rear axles. almost nothing else.
Oh, welcome to the forum.
A 351W is not the easiest of engines to swap in. They are taller than the 289/302s. Mustang II headers will NOT work. There used to be headers for the swap into a Pinto, you may still find them on Ebay.
Suggest you do a search here about the swaps, lots and lots of information.
Not saying don't do it, just get educated first.
Me, I am going to put a 351C in my 74 Wagon. But I am insane.
Oh, and pictures are pretty much a requirement here. :-)
Russ