I have a 98 F150 I just bought a few months ago with a 4.2 V6 and M5R2 Manual 5 Speed. I bought it as a project for $300, at the time when I bought it the transmission was shot, only had 1st and Reverse, so after fixing it I've put a couple hundred miles on it and don't really like how sluggish it is. I wanna swap a V8 into it but also want to keep it manual(hence why I don't wanna swap a 5.4L into it) I heard guys have done 4.6L swaps with the Mazda 5 speed, but don't know if it'll bolt on to any 4.6L or if it only bolts on to a certain 4.6, like a Windsor or Romeo block.

 

No won't work, the V6 shares a bell housing bolt pattern with the old 5.0/5.8 windsor motors not the newer 4.6/5.4 Triton motors. If the truck has anything less than 4.10 gears changing that would be money better spent than swapping in a 4.6L.