In a nutshell, there are only two styles of slant six rockers. The ones for solid lifters (has the adjuster screw) and ones for hydraulic lifters (no adjuster screws). Over the years, there may have been subtle upgrades or changes made, but nothing substantial. Basically, all slant six mechanical rockers are interchangeable (no intake of exhaust specific ones) with any other mechanical slant six rockers. Likewise, all slant six hydraulic lifter rocker arms are interchangeable with any year slant six hydraulic lifter rockers. However, you cannot mix and match between the two styles.
