1970 or 1970, when CA started putting their emissions programs in force.
255HP is a 360 rating. The 360 switched to rollers in 1989.... the 318 started in '85. Amazing what you can learn here LOL: LA - Chrysler small block V8 engines
If the OP changes from rollers to flat tappets, then he could use the 6901 (that would not be my choice though) but would have to change pushrods.
