700R4 Swap between C10 & C20

[Feldsine]

Hey all. I have a 69 C10 / 350. I put a 700R4 in it a while back, having the drive shaft cut down to fit and all that. It's been working great. Now I recently bought a 71 C20 that is in much better shape than my C10. I am considering swapping the engine / Trans / Drive Shaft into the C20.

My question is are the C10 / C20 motor mount or differential position / length going to cause a problem with the drive shaft length?

[MARKDTN]

Motor mounts are in the same place but the pinion on the rear differential on a 3/4 ton may be longer than the 1/2 ton one meaning the driveshaft may be too long (and the u-joint might be different).

[kwmech]

It shouldn't as long as the wheel base is the same, oops, yeah I didn't think about the u-joint and the length of the pinion from the center of the housing

[Feldsine]

Hmm, I was afraid of that. And I just realized that if I take the 350 / TB350 (or 400) out of the C20 and put it in the C10 I'll have to get THAT drive shaft modified as well. Geez... What to do.....

[hugger6933]

It will be worth it to build the driveshafts for both trucks, they probably need a freshen up any ways

[birshking]

Originally Posted by Feldsine

Hey all. I have a 69 C10 / 350. I put a 700R4 in it a while back, having the drive shaft cut down to fit and all that. It's been working great. Now I recently bought a 71 C20 that is in much better shape than my C10. I am considering swapping the engine / Trans / Drive Shaft into the C20.

My question is are the C10 / C20 motor mount or differential position / length going to cause a problem with the drive shaft length?

WHAT ALL WAS NEEDED TO SWAP TO 700r4?

[Feldsine]

What I needed to do to put it in a C10 was:

1. Getting a shift linkage kit from Lokar.
2. Shorten the drive shaft using the measurement instructions from the shop doing the shortening.
3. Moving the transmission mount cross member and redrilling holes to attach it back a little further.
4. I got a cable mount from Bowtie Overdrives so that the TV adjustment could be made properly. This plate goes under the carb and it probably the most important piece.
5. Make the electrical connections for the lockup converter.
6. Getting the proper speedo gear to the MPH is correct. I still haven't got this right yet.

I think that is about it.

[birshking]

Originally Posted by Feldsine

What I needed to do to put it in a C10 was:

1. Getting a shift linkage kit from Lokar.
2. Shorten the drive shaft using the measurement instructions from the shop doing the shortening.
3. Moving the transmission mount cross member and redrilling holes to attach it back a little further.
4. I got a cable mount from Bowtie Overdrives so that the TV adjustment could be made properly. This plate goes under the carb and it probably the most important piece.
5. Make the electrical connections for the lockup converter.
6. Getting the proper speedo gear to the MPH is correct. I still haven't got this right yet.

I think that is about it.

WHERE/HOW you get #5 done? stand alone computer?

[Boog]

The 700r4 isnt computer controlled. You just have to wire in a vacumn/electric switch and change the brake light switch.

[Feldsine]

Right, what Boog said. Wiring the lockup is pretty simple, although I have never been able to detect that it was actually working. When I transfer this to my C20, I would like to add an LED indicator lamp to show when it is on (locked up). You could probably just google wiring a lockup converter and get a wiring diagram pretty quick.