Driveshaft length using 1350 transmission and pinion yoke?

[jawbone]

Gentlemen. Hope all is well. Need help determining custom driveshaft length. The car is a 68 Barracuda with A833 and 8 3/4. Factory length, if I'm correct, is 48.6 inches. Modifications from stock is the use of series 1350 transmission and rear end yokes. Question is, is the slip yoke at the transmission spaced off the rubber boot 3/4 - 1 inch. The output shaft is 3/16 inch below the end of rubber boot. Inserted the slip yoke compressing the boot but never bottomed out. With the slip yoke approx. 3/4 inch from end of rubber boot, centerline of u joints is approx 48.6 inches. This will be a custom made driveshaft so need to get this right. Thanks for any comments.

 

[Newbomb Turk]

I bottom the slip yoke on the output shaft, pull it out 3/4-7/8 and measure.

I also don’t use the long seal on the tail housing. Never found the need to cover the slip yoke if it’s not out a mile.

You want the most spline engagement you can get. That means bottom it out, get it where you want it and measure.

 

[jawbone]

I bottom the slip yoke on the output shaft, pull it out 3/4-7/8 and measure.

I also don’t use the long seal on the tail housing. Never found the need to cover the slip yoke if it’s not out a mile.

You want the most spline engagement you can get. That means bottom it out, get it where you want it and measure.

That's full engagement you have; no doubt. I have the seal installed so different expectations. All my measurements come back to 48.625 inches. That's with yoke 2 inches from tail of transmission. Wish someone could confirm the 48.625 driveshaft length. Thanks for your comment.

 

[ESP47]

Ask the driveline company how they want the measurement to be done.

I'm the king of measure 20 times, cut once and it's still wrong so I was worried about screwing mine up too.

Mine was a TKX so the length isn't applicable but I just pushed the trans yoke in until it was touching the rubber boot but not squishing it. Then I measured center of the yoke u joint center to the u joint center of the rear yoke. When I got to the driveline shop the guy did a little of his own math from my measurement and it fit just fine when they completed it.

 

[jawbone]

Ask the driveline company how they want the measurement to be done.

I'm the king of measure 20 times, cut once and it's still wrong so I was worried about screwing mine up too.

Mine was a TKX so the length isn't applicable but I just pushed the trans yoke in until it was touching the rubber boot but not squishing it. Then I measured center of the yoke u joint center to the u joint center of the rear yoke. When I got to the driveline shop the guy did a little of his own math from my measurement and it fit just fine when they completed it.

Thanks for the response. Will let the driveshaft company do their thing as well. I know about where it should be.

 

[Desoto291hemi]

Shouldn’t the shaft length still be the same ?
I always thought the length was measured off the centerline of the joints ?

Tommy