Update, took my drive shaft into a different place to have it high speed balanced, this time I took some measurements of the trans to Diff, spoke to the guy, he measured things up and we agree’d my driveshaft was a bit over 3/4” shorter than it could be, that with the short slip yoke meant that it it’s length was possibly more important so I’m having a new shaft made, well we will see how this one goes. I had my suspicions it was on the short side