how long does my driveshaft have to be?

[71badblue]

my 71 short bed has no drive shaft. what size drive shaft do i need to put back in it? it has a turbo 400 tranny

[brad_man_72]

It has to be 2.5" from the tailshaft to the center of the first ujoint then whatever distance to the center of the rear ujoint.

Its usually best to give the driveline shop a tailshaft to center of rear joint measurement.

You have to measure your truck, theirs about a dozen motor mount combinations using stock parts so we can't really tell you how long your shaft needs to be.

If you don't have a trans yoke it will probably cost you $250 for a new one piece shaft, quite a bit more if you want a 2 piecer.
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[jocko]

if you get a ds from a swb TH400 truck - it should work. If you are going to have a shop make it, gotta do what brad mentions for distance, but also not most places provide an online form with detailed directions on exaxctly what to measure. Also - make sure to measure with weight-on-wheels (if you measure it unsprung, the shop will make an artificially too long ds).

[71badblue]

does 60 inches sound about right? i measured from center hole to center hole

[brad_man_72]

Originally Posted by jocko

if you get a ds from a swb TH400 truck - it should work. If you are going to have a shop make it, gotta do what brad mentions for distance, but also not most places provide an online form with detailed directions on exaxctly what to measure. Also - make sure to measure with weight-on-wheels (if you measure it unsprung, the shop will make an artificially too long ds).

Actually drive shafts get shorter with the wheels drooped. Not so much on trailing arm trucks because the arms are almost as long as the d.s. but on a leaf truck the wheels really move foreward at droop.

The odds of another 67-72 with a th400 driveshaft fitting your truck are low enough to not bother looking. Like I said there's about a dozen locations to mount your engine. L6 mounts , sbc mounts, bbc mounts, and they can all be swapped from side to side. Who's to say what's been done to yours or the donor truck over the last 40 years.
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[brad_man_72]

Originally Posted by 71badblue

does 60 inches sound about right? i measured from center hole to center hole

Bolt on trans yoke? If so the ds will need a slip and stub, preferably at the trans end. 60" is a possible length.
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