Slick 60's

I have decided to swap out the transmission that I have in my 1966 f100. It has a 300 i6 with the Heavy Duty 4 Speed (NP). This truck has been in the family since it was purchased. The only complaint that I or any of the family have about it is that it is very low geared. So after discussing my plans with my father (who was the previous owner) he informed me that at one point he wanted to put a splitter in the truck but did not want to cut into the truck any more than he already had. So after much debate we have came up with the idea of swapping out the current 4 speed with a 5 speed transmission. After a little bit of reasearch we both agreed on the TKO 600 5 speed tranny. So I now open this question up to my fellow slick60's people.
Has anybody out there done a swap out like this?

If you have what tranny did you use?

Did you have to modify anything other than the transmission mount?

What tranny did you use?

TKO600 is an expensive trans, and do you really feel you need a trans built to withstand 600ft-lbs of torque?? Why not cruise the wreckers and find all the bits from a later eighties to mid nineties F150 2WD with a 300/302/351-5 spd and swap them to your truck. All proven to fit, and withstand the power of a 300 I6........

James

You could swap in a M5OD out of an early-`90`s Ford pickup. Bolts right to your six, and the shifter comes up through the same hole, no floor pan butchering. The hydraulic clutch takes some fabrication, though. And the rear X member has to move back a few inches, just drill a few new holes in the frame. I used the original NP rear mount, it fit the M5 perfectly.

You could swap in a M5OD out of an early-`90`s Ford pickup. Bolts right to your six, and the shifter comes up through the same hole, no floor pan butchering. The hydraulic clutch takes some fabrication, though. And the rear X member has to move back a few inches, just drill a few new holes in the frame. I used the original NP rear mount, it fit the M5 perfectly.