Want to walk through project.

I recently came across an 87 Ford Mustang 4cyl and want to do some work on it. A friend of mine is giving me a 3.8 liter v-6, trans and wiring harness out of an 89 Mecury Cougar. Plus I have an 94 Ford Explorer and a 93 Mustang that has a blown tranny...unfortunately the 93 Stang has a 4 banger in it as well. I was wondering if there is a good combination here? Some info would really be appreciated. Motor and trans out of explore is a 4.0, 5 speed tranny w/166000 miles on it and the cougar only had 125000 w/3.8 liter automatic tranny. It has either a cracked head or blown head gaskets. Would any of this be worht combining or should I just fork over money for a 302 or 351?

If the 3.8 has a M90 I'd work with that, if its N/A then getting a 351 or somthing would probaly be a better idea.

What is an M90?

What is an M90? A supercharger.