I have purchased mine from Centerville. Have had it for several years, and it is a very solid and well machined piece. And I drive it like I'm 16 years old and I ain't got no sense.
Fort Wayne Clutch for the disc and pressure plate. (pretty much heavy duty standard style disc with torsion and cushion springs and diaphragm style plate) Disc had to be modded to inverted clutch disc. I spoke to Barney Martin barney@fortwayneclutch.com
American Powertrain makes the flywheel. One of our members called them and got a discount and free shipping, may be worth a try. https://americanpowertrain.com/shop...et-steel-flywheel-for-all-buick-401-nailhead/