Need FULL disclosure on TH350 to 700R4 swap

[68Timber]

I'm about to order a wicked crate engine. The rear end is going to get 4.10's and an Eaton Posi.

All I know about swapping an R4 for the TH350 is to move the crossmember back on the frame and drill for the new mounts. Shorten the driveshaft. Add a TV cable bracket to the carb and be sure to install the TV cable to specs.

A friend will be the foreman of this project and he's convinced it's not that easy. The first question he threw at me was tranny cooler lines. Never heard it mentioned, but I'd guess they have to be replaced too. He was also concerned about my column 3-speed shifter not working. And he mentioned yokes and spline counts.

I need the full scoop. He's all up to do the job if we know everything that will have to be addressed up front. He's a good bud, but not so much so to do the leg-work. I can put one in my truck. What all will it take?

Thanks,
John

[tvblazer78]

Blazin, about 8 years ago I put a 700r in my blazer and the only thing that I had to change was the kick down, crossmember, dip stick and a B&M lock up kit. The only thing that you may have trouble with is spline on your drive shaft. What year is your trans? I do know the number of splines changed in the 90's. so just look into that and you should be good. And your drive shaft should work if it is a long teil.

You can change you 3 speed display and put in a 4 speed, but I never did and it worked fine..

Hope this helps..

[68Timber]

Thanks Trav, that's the kind of extra details I need. Did you reuse the cooler lines? I don't know the spline count, but it's a TH350 in a '79 - I guess it's original but who knows.

[tvblazer78]

Originally Posted by Blazin79

Thanks Trav, that's the kind of extra details I need. Did you reuse the cooler lines? I don't know the spline count, but it's a TH350 in a '79 - I guess it's original but who knows.

Yes the cooler lines should be the same. What year is the 700R?

[68Timber]

I don't have one yet. I'm going to visit family for Christmas this weekend and I'll see a cousin who used to own a transmission shop. I'm going to see if I can talk him into building one more... He's the only one I know and trust to build one to hold up to what I'm going to put it through.

[Jonboy]

I put one in my 77 2wd. You will need to drill the new holes in the crossmember, get a bracket for the TV cable (and a cable if you don't get one with the transmission), a lockup for the TCC, and the driveshaft will have to be shortened. When I swapped mine out, I was able to pirate everything out of an 82 2wd, so I am not sure how much the driveshaft will have to be shortened. The cooler lines should work just fine.