Just ordered a new driveshaft from Driveshaft Replacement of Texas for my '78 coupe. When I restored my Z, I replaced all the mounts on the engine, tranny and diff, but the driveshaft was wonky and is now bumpin and thumpin. Although my diff mount is near new I am thinking that my next upgrade will be a Technoversions Diff Mount - (BUT their website is down so if you have a contact #, I would be much obliged).

Driveshaft Replacement of Texas is charging $279, the driveshafts are built to order using new parts, replaceable u-joints and is speed balanced. The price also includes shipping. I will do a follow-up post with comments on quality of workmanship, fitment, etc. Plus lots of pics.

Ask if possible for a "race" balance. Speed balance is fine for a Jeep but not a unibody sports car.

They balance to 150 mph, which is faster than I'll ever put it through.

That's a good price. Let us know how you like it.

So I performed the transplant on Saturday and all went pretty slick. The new driveshaft is a near perfect match for the original. The hardest part of the effort was unbolting the damn thing.

As for the quality of the new driveshaft, the welds were on par or better than the original (see pics). The serviceable Spicer u-joints are a great improvement over the old staked in version and the yokes are spot on with the originals - except for lacking the dust shield of the original. After a test-ride, I can say that I am very happy. Big improvement with no noise or slack.