summit says my car comes stock with a 10" flywheel, and to use these 10.5" clutches i need a 10.5" flywheel, i've never heard this anywhere else..but it makes sense... is this true?
based on your sig, I assume you are talking about a 93 mustang 5.0??
summit is wrong, sounds like you looked up the specs for an 85. if it's for your 93, it's already a 10.5 inch clutch
fyi, for all of those out there with 85 and olders, if your mustang is an 81 and newer, you have the 50 oz balance, and to swap to the 86+ style clutch, all you will have to do is get an 86-93 pressure plate. Additionally, with the bigger 10.5 inch clutch from 86-93, ford switched the pressure plate bolts from standard to metric, so for those upgrading an 85 or older, you'll have to obtain pressure plate bolts as well from an 86+. the flywheel bolts can be re used.