3 speed to TH350 swap - right choice?

[Mark B]

I have a 1970 with a 3 speed and 250 six and am considering a swap to a TH350 that I have in a 1970 donor vehicle, which is also a 250 six. Is that the right direction to go? Or it it better to swap to a 700R4? Would a 700R4 it fit the six? Is it an easier or harder swap than a TH350?

thanks very much
Mark

[raycow]

All else being equal, I would always go for an overdrive transmission on any vehicle that gets driven at highway speeds.

Yes, the 700R4 will bolt up to your 250. It will be slightly more difficult to install than the TH350. You will need to shorten your driveshaft, cobble the TV cable mount and wire the converter lockup. I'm not mentioning the radiator, cooling lines, crossmember, and shift linkage because you will have to do those with the TH350 too.

Ray

[Critter]

Originally Posted by raycow

All else being equal, I would always go for an overdrive transmission on any vehicle that gets driven at highway speeds.

Yes, the 700R4 will bolt up to your 250. It will be slightly more difficult to install than the TH350. You will need to shorten your driveshaft, cobble the TV cable mount and wire the converter lockup. I'm not mentioning the radiator, cooling lines, crossmember, and shift linkage because you will have to do those with the TH350 too.

Ray

100%. The th350 might be slightly easier to swap but the overdrive 700r4 would would be much better in the long run. A few guys around here have made the 700r4 swap with a 6cyl, I'm sure somebody will jump in with more details.

An even better swap in many peoples eyes would be a 200r4 overdrive...but they are harder to find.

[Sinister]

A 200-4R will bolt right in without have to mess with the driveshaft from what I've heard. ebfabman did this swap.

[57larry]

I use a turbo 350 in everything I build. Anybody can rebuild one. Change the rear end gear, but 700R4's are good if you're going to tow