you want to keep it standard or u wanna go automatic? do you race or do you "putt-putt"? how deep are your pockets? how many gears do you want? whats the rear end ratio? I ask all of these because if you don't want a standard, a nice TH350 or a 700r4 would go great for a cruiser. If you race, you obviously want a little stronger built tranny. Some transmissions cost more than others. Sometimes a 6 speed is more fun than a 3 speed or an automatic. Your rear end ratio matters because if you drive the car everyday, then you wouldn't want a 4.11 and a 3 speed. So you can select your trans. according to these questions basically.

But if you want the t10, which is a pretty good 4 speed transmission, eBay is always a pretty good spot to snipe these out. You could also check around at some local transmission shops and see what they can offer?