I'm measuring for an adaptor plate to mate a chevy bell housing to my Land Rover autobox (ZF - same tranny as most BMW, Volvo, etc). Maybe I'm just overthinking it, but I feel like the tolerances must be pretty tight to ensure proper input shaft alignment with the torque converter?
Or are the holes over-bored to allow the engine to self center before tightening everything down?

First swap - so I'm clueless!

 

Typically the bolts don't do the centering, the alignment dowels do. And yes it is critical to have the two centered perfectly.

 

Gotcha. Is there a method to the madness aside from very careful measuring with good calipers?

The plate will fit between the input side of the 4HP22 transmission and the chevy 4L60E bell housing.

 

You need to find true center of the bell and trans, then match them up.

 

Thanks, will do. I'll have some centering dowels machined in too. Going to CAD the plate up and have it cnc'd out at my friends work (incidentally in Vancouver )