I recently purchased a FF 1600 flywheel machined for a 7.25" clutch. After cleaning off some slight surface rust, it appears the raised "step" is .090". In the book, How to Build and Maintain Competitive Formula Ford 1600 Engines, the recommended step height is .097 to .100". Tilton also recommends a similar measurement (.098" - .100"). My clutch disk (used) surface measures .098", within the minimum of .074". The "stepped" portion of the flywheel face shows no wear and is in great shape, as is the rest of the flywheel.
Do I need to machine another .007" to .010" off the flywheel to increase the step height, or is the .090" step enough?
Best regards,
Lowell