Sxynerd

It doesn't matter which Alternator you use. I think the only real difference is the plug and the some NPI Alt. have an "eyelet" for the lower two bolts to go through and the PI is just a half crescent. The dimensions are the same along with the electrical aspects.

[I did forget one thing about the Alternator.]

The upper support bracket is what's going to give you the most issues. Swap the brackets back and forth and see what you can make work. I didn't even use the factory bracket. Two pieces of flat stock aluminum and drill a whole in each end of it and bolted it down. It's just there for torsional support so use what ever you have handy.

(I would always keep the extra alternator in case of emergencies. They're not cheap.)

stalkr

why not just get a 5.4 block. its as simple as swaping a pi 4.6. you'll need an 8 bolt flywheel, in some cases the belt tensioner assembly, and i thing thats about it. My 96 mustang had an 01 gt engine but it blew up about 5 weeks ago. Now i have a 5.4 engine out of a f150 with stage 3 ported heads and stage 2 cams waiting to be install. i just need to install the kmember, a arms, and coil over(i had all this parts before my engine blew up). i hope i can hit 12s with this set up.

Sxynerd

Because there's no extra HP in a 5.4 and it still has the crappy internals and weighs more.

stalkr

well i had my car dyno tune before it blew up and it was pulling 270 hp and 300 tq. ill let you know my new numbers after i get it all done which should be in about 2 months. the only extra thing is the ported heads.