I have a new flywheel for my '68 400/4-speed (in a '67 hard top). The new flywheel is drilled for both 10.5 and 11 inch clutch. Any problem going with the 11 inch? Bell housing clearance or anything? Why is there a choice?
The only real difference is in the disc diameter. The pressure plates are not that different and the Pontiac bell housing was designed to take the 11" clutch without any clearance issues.
McLeod makes a pressure plate that fits the 10.5" pattern and takes the 11" disc. Talk about the best of both worlds!