8cyl swap

my dad's shopping for an old mustang, like a '64 to '68. The only problem with that is he keeps finding the 6 cylinder models because he only wants to spend like $5,000. The old 6 cylinders are SLOW so i was wondering if i was to drop in a 289 would i have to change the tranny too? i know i'd probably have to fabricate some new mounting brackets , but im trying to keep the swap as cheap as possible. what would i need?

Teh trans would be fine, the bellhousing now thats a different story. I'm not 100% sure but I'd say its a good bet that that trans won't wold directly to the V8 from the 6. Other than the bell housing though I don't think too much would be different.

Guess you've only driven stock ones. You'd be surpirsed what a warmed up 6 can do. Anyway, you do NOT want a 6cyl transmission behind a V8. Pre-67 6cyl transmission are not very good at all. In 67 they changed things and used the manual 3.03 transmission similar to the v8's. There are some big differences though, 1st is that the 1st gear is higher, 2nd is that the bell housing is different as already said. I would stay away completely from auto. You're best bet is to hunt down a v8 transmission or in better yet, wait til you find an afordable V8. It takes time but certainly can be done. You need to do a lot more than just drop in a 289 and go. You have to switch to the v8 5lug front and rear ends. This engine is heaver, the v8 gear is heaver, a stock 289 is going to be slow too.