Slant 6 block casting numbers

Unlike the V8's, the /6 casting numbers do not have the displacement number in the middle. It ought to be a 7 digit number, followed by a '-x' where x is a 1 or 2 digit number, corresponding to the casting station/machine.

Older /6 block numbers were on the driver's side of the block; look there around the core plugs (freeze plugs). I dunno about later. The expert at /6 casting numbers is slantsixdan. You can aslo get good info over a www.slantsix.org .