TH350 to 700R4 transmission swap question

[vern350]

Whats needed if anything to swap the TH350 to 700R4 in my 81 c-10shortbox. I looked at it quickly and it looks like the 700R4 will bolt right up with the same crossmember and driveshaft? Thanks

[country29]

yes it will use same crossmember but will have to use th700 trans mount and may have to drill new holes in frame for crossmember, and you will probably have to shorten the driveshaft a couple inches, from what I remember. and you will have to add bracket for tv cable on carburetor, and will have to reform cooler lines slightly, but nothing major, just a few lil changes and it will bolt right up. just my .02

[85gmcguy]

Your crossmember will work fine, but you may have to drill new holes because it will move back a little. Driveshaft may or may not have to be shortened. Mine fit fine without cutting. You will need a new throttle cable bracket with a TV cable provision, and also a way to lock up the convertor. Painless makes one, but Speedway has pretty much the same thing a little cheaper. Check out www.bowtieoverdrives.com. They have a great tech section!

[HOGDADDY]

Yea I ended up using 2 original holes on crossmember and drilling 2 new ones I believe and my driveshaft fit fine. I even used the th350 rubber mount too I believe cause I don't remember buying a new one.

I did however have to clearance the crossmember for the B&M aluminum deep pan somewhat with my cut-off wheel but I think the pan adds to the rigidity of the overall tranny case.
The fins maybe help cooling and xtra fluid can't hurt either. It also has a drain plug and temp. sensor plug.

The best filter imho is the TCI unit as it does not suck from the bottom but from the topside.

Why I don't even use a xtra cooler only stock one in radiator.

If you need a dipstick/tube get the locking one from a 97 silverado 4l60e. from G.M. new was reasonably priced.

[3r!c84]

ive always hurd of shorting the drive shaft? but i may be wrong

[HOGDADDY]

Originally Posted by 3r!c84

ive always hurd of shorting the drive shaft? but i may be wrong

I promise ya my stock onefit fine in my 86.

I also used original tranny cooler lines. leave them disconnected at the rad. connect them to tranny first then tweak em at the rad. last. for trouble free install.

[3r!c84]

nice, how much slip room (movement) room is there in the drive shaft?

all i gotta do is find a 700r4 ! save me on gas

[vern350]

Thanks for the replies. Looks like its not much difference. Will report back if I get around to doing so.