If you think it will go in go for it.
6.4 diesel or 5.4 modular? the 6.4 diesel would be pointless and require a lot of fabrication, the 5.4 modular requires a custom intake manifold since the block is about an inch taller than the 4.6 (10.07 inches vs 8.93 and weighs about 30 more lbs) horsepower is still 260 for a 5.4 sohc 2v but torque is 350 ft lbs instead of 302 that the 4.6 produces. Most people who do the 5.4 swap use the dohc 5.4 from the lincoln navigator (it offers forged internals as well) they produce 300 hp and 355 ft lbs of torque.
I asn't gonna go with a diesel because yes it would be pointless. I could go with a 5.4 but I just wanna do something a lil more dif. especially with a 6.4 if there are things that I need to move around and pluz cust. make things just to make it fit and work properly aswell as produce the right amount of horse power than yes I'm willing to go for it I'm just thinking what would be the best 6.4 block to use to do so
The 390 is not a good engine in stock form. You'd be better off with a small block modular.
If you're bent on a 6.4 you're going to have to cut the front strut towers, buy a k-member and get a cowl hood just to get it to fit, then mod the hell out of the engine to get it to make power.
Looking for a Used Mustang in your area?
CarGurus has 45,096 nationwide Mustang listings starting at $2,000.
Search Ford Mustang Questions
Ford Mustang Experts