non dodge 6bt clutch question

[txs]

OK, I've found a flywheel for the #3 sae housing I have to put the 6bt into my oliver, problem is it's dual bolt pattern for the pressure plate. 10" and 11 1/2". The actual diameter of the sae #3 flywheel is over an inch bigger than the dodge flywheels, why they do that? Wonder if I can find a 11 1/2" clutch that will pull a 6 bottom plow. Hoping for enough machined area to drill and tap a bigger pressure plate bolt pattern.