Not sure if Whitbread does TDI to Chevy, he does BMW to Chevy. He puts inserts in the aluminum. Look at Doomsday, I think he might do a thin adapter out of steel that bolts to the pan. I imagine the shorter the better for you? Quite a few companies making TDI adapters. I would be looking for something I could use an 11” clutch with and incorporates the TDI oil pan bolts for rigidity. The old Chevy truck bells had cross member mounts on them and also a cast aluminum inspection cover