Ford questions from a Chevy guy

[MuscleCarFanatic]

First off, Its cool to be on your message board. Here's my situation...My brother is looking into getting a 67-69 Ford Mustang and working on it, much like I have done with my '68 Chevy Camaro. We have always loved all old muscle cars, and I completely encourage him.

Thats why I'm here, to help him with his research. Anyways, here's my questions (keeping in mind I know nothing about Ford engines and such)...

1)What are the differences between Ford truck and Ford passenger car engines?(ie. chevy truck engines generally have higher decks than thier car engines I believe)

2)We are planning on getting a Mustang with a 289 and probably dropping in a larger engine. I believe that 67-69 mustangs are wider than the earlier ones, but how big of an engine does this allow to fit? I heard somewhere 390, but I have seen some bad *** mustangs with 428's (didn't the GT500 have a 428)?

3)What opinions do any of you have as far as a good steet motor for Mustangs of these years? (289ci+) It'll see some hard driving and a little street racing against a local "Team" of Imports, but will also be his daily driver, atleast for awhile.

Thanks for the help...