Dr. Diff lists them. https://www.doctordiff.com/1350-to-7290-conversion-u-joint.html

He also lists 1350 yoke for the 8-3/4 rear axles. https://www.doctordiff.com/1350-u-bolt-pinion-yoke-package.html

i need a new driveshaft made for my charger because the joint "ear hole" on the front of the shaft [the shaft has the damper ring on the front if that matters] has become slightly egg shaped, allowing play in the shaft between the joint cup and the front ear hole of the shaft.
with that said, what i would like to do is get a shaft made with a forged yoke for the 727, and use 1350 joints on both ends of the shaft.
with that said, however, is there a 1350/7290 [or 7260] conversion joint made ?
the reason for asking is, i am keeping the 8 3/4 rear the car came with, and i have several sets of 3.91 gears, all in 742 or 741 cases, having the 7260 joint size on them.
i have a good 7290 pinion yoke i can swap [just remove the 7260 joint, replace seal, install 7290 yolk, torque down with a new nut and done ?] so i figured i would do that, but have a nice 1350 joint shaft, if and whenever i decided to purchase a 1350 pinion yolk.
please show me where i am screwing up, but remember, the 8 3/4 will be staying. TIA !

hmmmm.............
i know it's none of my business, but would it be possible to pm me with the story ?
as you know what i have to deal with, my funds are only few and far between to attempt to get my junk back on the road, so i have to be judicious with my spending in order to be able to afford other costs in my life that are way more important.

as you know I have an a518 [46rh] OD trans, lots of potential drive line angle issues, so I had a Alum shaft made here in houston by a well known company, $750, FOUGHT & FOUGHT a drive line vibration, ie EVERYTHING possible LOL, pinion angle,trans angle ect, I gave up, blew up my 8 3/4 & had to get them to shorten the drive shaft $150, now the vibration was WORSE, took it back to them three times for a rebalance ,,, NO change, in desperation I ordered a Strange steel custom shaft $450 & it changed the vibration considerably but at high speeds it came back, I called Strange & asked them what RPM they spin the shaft for balancing, they said, 500 rpm was the fastest they spin them, so I did the old chalk marker test on the shaft on jack stands at 60 mph, the chalk marks were at the same spot as the welded on weights, so I cut them off & ended up adding weight almost opposite of where they had them, the vibration was ALMOST gone but at 120mph it was still pretty bad, so, I called Mark Williams & asked them what RPM they can spin the shaft, They said as fast as you want, so I had them build me a new shaft $650 with their better yoke, the car is SMOOTH as GLASS !!!!!! another one of my expensive lessons learned the hard way & yes I have the large u joint 1350