I'm trying to figure this out, but for some reason keep coming up short. It's the 2806070 fan clutch off my 68 Road Runner. The date code stamp on the front says J 11 H. Is this correct for my 68 RR that was built July 3rd, 1968? I also have the fan too and my car came with a 26" rad originally with the HD axle package too, so it's supposed to have this but want to see if that date code matches. Thanks.

Cheers

Don't know if this helps. The fan clutch on my 68 Coronet has date code F 11. It's a 318 car, air conditioning, 26" radiator. Car build date is June 26, 1968 at St. Louis.
Since yours is a July car your date code makes looks like yours has later code than mine.