so my car was an original 700r4 car and im now swapping everything over and i was just wondering if the stock drive shaft will work or if i have to get a different length and such?

 

depends on the tail shaft length of your trans a 9inch shaft will let you keep your stock drive line but youll need a conversion u joint for the th350 yolk and a bracket kit for your torque arm summit sells them most gm trucks had the 9inch shaft

 

im getting a transmount with the relocation bracket so no worrys about that. how do i tell what the length is?

 

I used my stock drive shaft and yoke, but the 700r4 was a 89 and so was the drive shaft if that makes a difference.

 

Measure the tailshaft housing length
http://www.tciauto.com/tc/trans-dim#TH350
http://www.tciauto.com/tc/trans-dim#700R4

As you can see , the most common TH350 with the 6" housing is 3" shorter than a T700 so the new DS needs to be that much longer

Both trans use the GM 27 spline yoke with a Spicer 1310 series uni; only HD vehicles had a larger uni fitted

 

If you end up with a short tail TH350 the driveshaft from an 82 (and maybe 83) will work.

 

TH350 with a 9" tailshaft can use the 700R4 driveshaft
TH350 with a 6" tailshaft needs a driveshaft from an 82-83 third gen that came with the 200c 3 speed transmission.

 

Depends. The 700-R4 passenger car slip yokes are going to be compatible with any 6" or 9" length TH350 and stock will have 3R u-joints. There are some TH350 slip yokes with different u-joints that could be used, but going to a "wrong" part only to use a conversion u-joint (less ideal if it can be avoided) isn't really a good direction to take.

 

that sucks because mines an 82 with the origional driveshaft its just that the shaft hit the pavement while towing it

 

OEM shafts are not that great anyway.

Take the slip yoke off the shaft. Slide it into the transmission all the way then pull it back out 1". Measure from the center of the slip yoke u-joint to the center of the diff u-joint. That's the exact length you need.

Take the driveshaft and yoke to a driveline shop and have them make you a new driveshaft. They can cut the tube off the yokes and install a new tube for the proper length. A better upgrade is to buy 1350 series slip yoke and diff yoke and have the driveline shop make a new driveshaft with 1350 series weld yokes as well. It will cost a lot more but you will have a much better driveshaft.