We initially decided to gear the ATV very low, so we would have lots of torque and not so much speed.  We accomplished this by using a 72 inch rear sprocket (see below for additional problems and why you can skip this entire procedure).  By the time we had the frame built and the engine and torque converter purchased, we realized we had a chain clearance problem - The chain would be too low to clear the trunion properly when the trunion flexed in certain positions - So Sam got out his slide rule and made some calculations.  The easy solution would be to raise the whole engine up an inch, but we didn't have the clearance under the seat.  So we decided to rotate the torque converter and raise the back edge (with the chain sprocket) one inch.  To do this we had to drill additional holes in the Converter mount - Sam designed a template for us with instructions.  Here's what we did:

1.  With the template level and taped in position, we cut out the three mounting holes (our engine only has three)

2.  We then measured and rotated the template so point B was one inch higher, and cut out the new holes (making slots) - we also marked another mounting hole found on our engine:

The rest of the torque converter was then mounted:

3.  We then put the template on the mount plate, lining up the original holes, and drilled the slots and new hole - When mounted, this raised the sprocket up 1"

This shows the rear end setup, with the chain fitted on the sprocket in the torque converter, with clearance on both sides of the trunion.  We haven't cut the chain yet so its too long.

This all worked out fine, until we put together our 72 tooth sprocket with our 18 inch tires (also purchased for high torque/low speed).  We then discovered we had less than 3 inches of ground clearance under the sprocket - not good.  Solution is a 60 tooth sprocket (also much cheaper) and/or 20 inch tires.  We'll probably go with the 60 tooth sprocket, and then weld on a sprocket guard. Of course, with a 60 tooth sprocket, we need to move the torque converter back to its original position.  So, we strongly reccommend going with the 60 tooth sprocket and skipping this entire process of messing with the torque converter.