The first Cruiser was the BJ, and it had a 4 cyl motor. The 6 cyl F motor didn't appear until the fj25, which was in the late 50s. The F is sort of a metrified 235, and it did not have full filtering until the 2F in 1974. The *F motor lasted up to 1988 when it was de-stroked and EFI'd into the 3FE. It became a DOHC, 24 valve 1fzfe in 1993 with an aluminum head and 7 main bearings.