AMC Gremlin

[fury fan]

DON'T weld it. It will alter the metallugy to an unknown extent.
For those 2 bolts - use Grade 8 bolts/nuts and hardened washers to get the most capacity.

Bolts in tension are stronger than bolts in shear (for same components). But bolts in a case like this would ordinarily be put in double-shear, which then exceeds the tensile strength.
But that's all immaterial with this hitch-ball.

 

[Just Carbs]

I'm thinking weld the block, then bolt ball with 1/2 course thread 25,000 lbs tensile load bolts.
Besides, it's going to bend that down bar before anything else happens.