You could take your flywheel off and drill it if it will mount to a flat part of the flywheel. If three holes line up with the existing holes you can put some kind of paint or transfer material on the new locations and then bolt the convertor to the flywheel to transfer the hole locations. I would first contact the manufacturer of the convertor to find out what they were thinking. Maybe they expect you to use the three that line up and call it good? GM had six bolts for some reason.