[Fox Body]

GT-40 heads will work, but the bolts are 7/16 while the 351W head bolts are 1/2" so you would have to drill them to account for this.

You'll have to get a diff flywheel and 351W swap headers. Would you plan on leaving it fuel injected? if so, I think you'd need the EFI conversion kit and you can use your upper intake (I think), but you'll need to get a Ford Motorsport lower intake. You will have some screwy stuff with the pulleys depending if you wanna keep 5.0 pulley system (brackets and all) or the 351's. The water pump will need to be a reverse flow water pump if you put the 5.0 one on the 351 (I think that's it).

Makes me wonder though, why change to 351? for the money it takes you to swap the 5.0 for the 5.8, and just bolting on some old Gt-40 heads, you could put that money into your 302, get some trick flow heads, etc. I don't think it'd be worth the time and effort to do the swap unless you do more than just bolt some GT-40 heads onto a stock Windsor--which would take money, WHICH would be money you could just put into the 302....