I have what I'm pretty sure is the original driveshaft for my '68 H/O, but I'd like to verify it is the correct driveshaft before duplicating it. I need to get a new one made, the car is taken apart, so I can't take the typical tailshaft to rear end yoke measurement. The car has short tail shaft TH400 and stock O-type rear. Can anybody here confirm if these two measurements below seem consistent with their experience?

Measurement from u-joint center to u-joint center: 55-1/4"

With the driveshaft installed into the trans, leaving 1" of slip distance (which matches the trans seal lip with the rusty area on the driveshaft), I measured 58-1/8" from the trans tail shaft housing to rear u-joint center (this imitates the measurement driveshaft manufacturers typically want). I attached a picture of this.

The car had been hot rodded in the 70s, so I'm starting to second guess if maybe this driveshaft could have been grabbed from some junkyard application sometime back in the '70s.

If anybody has a way to validate these measurements, whether from a known driveshaft laying around or a previously ordered piece, I'd appreciate it. Thanks in advance!

 

Luke, is there a part number on the drive shaft ? Turbo 400 was much easier on drivetrain than manual transmissions, and I never had a failure. Why duplicate the drive shaft ?
Maybe Joe or someone can find a part number.
Ralph

 

No part number that I can find. The automatic trans cars got a two piece driveshaft with the halves bonded together by rubber... I'm planning to race the car at the Pure Stock drags, and don't want to take the chance of grenading one. A broken driveshaft can crack the trans case, and since this is the numbers matching trans, I'd like some durability...

 

I don't recall a driveshaft with two bonded halves. From something I read in another thread, a driveshaft was mention and it sounded like an inner and outer tube was bonded together. I believe Joe P. gave the info.
I can tell you drag raced in NHRA Stock with a completely blueprinted engine from Berejik Olds, Hooker headers, 4.33 gears, 7" M&H's and Goodyears @ 8 psi and never had a drive shaft failure.
Ralph

 

Luke, just measured D/S from my 70 442 auto, one piece, 55-3/16" center to center of the loops, and 58-1/2"-ish to wear mark on yoke.

Brett