I am running a pinion snubber but have it about 3/4" off the floor. I will check the shocks for dents, thanks for the help.

You stated that your driveshaft is 3/4" shorter then you would like it. What is that number? At rest I like it to be 3/4" max.

Went through a phase of breaking these a few years ago. checked driveshaft at the shop that made it...Ok, Changed trans mount from stock to urethane piece, and checked length and pinion angle... broke one. Added an engine limiter and snub bars to the cage... broke one. Had the drive shaft checked for balance and out of round at another shop... said it was "ok", broke another one. Ordered a brand new aluminum shaft from Inland Empire Driveline... never broke a tail again.

It was funny... the change that I made was putting my newly ported heads on and went from running high tens, to low tens/high nines.

last year on the wednesday test and tune before Monster Mopar. broke on the launch, never knew it. i oiled down the entire length of the track, i couldn,t apologise enough. had made a 4 link change and thought that was the cause, letting yoke bottom in tranny. what happenned is engine limiter mount bolt had nut come loose allowing eng/tranny to move enough to bottom yoke out. i check that nut alot now.

Here is a couple of pics. The yoke has about 5" of spline with 3.25" of it engaged on the output shaft and 1.75" hanging off the end of the output shaft with the car at rest with weight on its tires. Do you guys think maybe the shaft is too short? Just to clearify this is a stock low compression 440 short block with a set of 906 heads and Comp magnum 292H cam, 2800rpm convertor and a stock tranny. Thanks again for all your help.

one more with the tail shaft housing slid back into place to show how far the yoke is into the tranny.

I had the same problem after buying a driveshaft from a reputable shop. Took the shaft to another shop, they said it was out a tiny bit. They fixed it and no more problem.

In your case, I think your shaft is a little too short. you might have to get a new one made up.

Thanks for the input, guess I better get the driveshaft checked out and maybe even a new tube to make it a little longer. How far into the tranny do you want the yoke to go? Should I be using the bolt on spring clamps and keeping the leaves really tight on each other?

You state that you are running a pinion snubber. Pinion snubbers and S/S springs are not to be run together. They will load and unload many times on the track.

The old Direct Connection manual said the correct driveshaft length was determined by measuring from the rear of the tailshaft to the center of the rear end yoke bearing cup minus 3.5"