I have a 64 f100 with a 292 4spd. I have decided to replace the 4spd with a 3spd, because the 4 speed is geared low. What year 3 spd. out of any kind car made then can fit on to a truck 292 y-block v8?

 

A 64 down unit is a bolt in with drive shaft mods.

you can upgrade to a five speed S10 or mustang T5 with the correct adaptors from Mummert.

Garbz

 

For about the same mount of money, and a whole lot less trouble, if you have a Ford 9" rear, change out the rear differential center punkin for a very low geared one, say 2.75 or 3.00.
You'll lower your RPMs significantly, and be able to use 1st gear as your starting gear.

Besides, changing the transmission won't change the final ratio, it is the same for all transmissions except overdrives: 1:1.
Changing the transmission from a 4 speed to a 3 speed will only give you a higher 1st gear, that's all.