The solution is in fact simpler.
I order laser cut Weldox steel parts with VW bolt pattern (few $$) and I will weld it to the machined Chevy Bolt transmission output shaft.
I assume that Reid understands that, and is referring to the shallow notch on the far outside edge of the machined Bolt cup which is visible in the rendering.
I assumed that this feature is not intentional, but just the remainder of one of the axial grooves which are normally found in tripod joint cups (and are visible in the photo in posts #105 and #50
), but it's a good point - the heads of the bolts (or the nuts on them) which hold the VW joint to the custom flange need to clear the material of the Bolt cup.
It's the same solution I used for my Smart 10 years ago and everything is fine today despite the max torque at CV joint is higher on the Smart (1600 Nm in first gear compare to 1250 Nm with the fix ratio of the Bolt)
I have no doubt that the welded joint can handle the torque.
That welding, and especially with a joint which is not simply circular, does raise the issue of balance. Before welding all of the parts will be rotationally symmetric and balanced. If the weld filler material is not perfectly evenly distributed, the balance will be slightly off. I assume that the plan is to get the completed assemblies balanced... or is the imbalance expected to be too small for that to be an issue?