I am about to swap out my transmission with a better one and my dad was wondering if he coud use my old one (which was just rebuilt) in his '85 Chevy LB Silverado. He has a 350 in it now but it leaks pretty bad, and he could use the overdrive. My question is: Is this a direct swap, and if not how much work would it take to install? My main concern would be the length of the two transmissions.
Thanks for any info or past experiences.

 

for the most part yes. so long as the th350 has the 6" tailshaft, you won't need to replace the driveshaft. you will need to get a lock up switch from someone like b&m or TCI. also, if his truck is carburated, then he will need to get the TV cable bracket from a junkyard or TCI. the current TV cable may not be long enogh. they make a universal TV cable.

 

If the TH350 has a 9" tailhousing, the driveshaft will fit. If the
TH350 is a TH350c, the lockup wiring should plug on ( and if the
lockup on the TH350c worked, it should work on the 700-r4).
Use the TV cable and bracket for a 700-r4 , as well as a gear selector bracket and fluid indicator and tube for the pickup with
a 700-r4. The crossmember may be the same, but be prepared
to buy one at a salvage yard . If in doubt, ask your salvage yard counterman.

 

Thanks a lot guys, that is what I needed to know.

 

uhmm a 700r4 is the length of th350 with 9" tail

6" tail is car length

6" tail th350 is 3" shorter than a 700r4

you guys shouldnt give wrong info out

 

Just helped someone do this swap. Had to weld a small piece of metal to the crossmember for trans. mount, used the 700 detent cable (required different throttle cable bracket for carbureted application). Driveshaft yoke fit on tailshaft splines o.k. Can't remember any major difficulties-just took a bit of enginuity. Both transmisssions were nearly identical in length.(measured before even CONTEMPLATING swap) Trans. mount on 700 was about 3 inches behind 350 mount hole in x-member-no big deal to modify. Owner loves his new trans. Gotta love that extra-low, tire fryin first gear.