All 429 cobra jet heads got guide plates, the differance was the stud, not that one had a guide plate and the other didn't. although i do not know the spec part, other than ford used special a lot for their high-performance engines. (in the parts books boss 302, boss 429, and boss 351 engines...
looking at the partial serial number, the 1st 1 looks like a 4 year i know it does not make sense. the F does look like an F, but could it be a P? maybe this engine is a 1971 429 police interceptor from a car built at the twin cities. again it does look like an F. and before you all get...
The correct tranny for a Boss 351 is the RUG AV1. The other trannys were either produced before Boss 351 production (RUG AV which was used in 1970 only) or after production (RUG BJ, they weren't used till 12/1/1971) way after 1971 mustang production had ended. A RUG BJ would be correct for a...