68 f100 3sp to a 4 or 5 speed

[TimB]

Just got our Father /son project April 1st. She is a 2 wheel drive shortbed with the 240 six and 3 on the tree. Plans are the 240 will remain. The non syncro 3 speed and column shift must go. I want to convert to 4 on the floor or better 5 on the floor. Wanting good top gears for gas mileage but still low end for pulling the boat up the launch ramp. What works as a bolt in solution. Keeping in mind we are planning on doing the disc brake and power steering conversions.
Our goal is a reliable, driveable, stearable, stopable, economical truck. We want to use factory FORD products. Note sure of the rearend ratio yet but it is stock.

[68shortbed]

The passenger car toploader is a simple swap, you'll gain a gear, but your final drive ratio will remain the same as the three speed. Sounds to me as a five speed out of a mustang or a later model ford truck with fifth gear as overdrive is more what you're looking for, those swaps i haven't done. My dad bought a new 88 shortbed with a 300 six and a five speed, that truck was peppy and got good mileage, it had 3.50 gears. My 68 shortbed came with a 240/3 sp. and 3.70 gears, i think with either of those ratio's and overdrive would give you what you want, check the tag on the rearend.

[sargentrs]

The Mazda M5R2 5-speed appears to be a relatively simple swap. http://www.fordification.com/tech/M5R2_5spd-swap.htm

[TimB]

sounding like a 4sp with some 3.0 to 3.25 gears in the rear might work. Son wants the shifter on the floor. Oh and a long shift lever that looks like it belongs there.

[68shortbed]

Ford did have a toploader that 4th gear was overdrive they used in mid 70's granada's, don't know what else. I bought 4 toploaders off a guy once and got one in the deal. never used it but it was identical to the older tranny's, you could still bolt a hurst shifter to it. Guess it depends on what you want and what you can find, that mazda swap sargentrs mentioned would give you what you want, plus a long shifter.