Starter position.
Older trucks and maybe some industrial equipment with the hydraulic bellhousing use a lower starter position, but as far as I know all cars with the slant six use the higher position.
Actually, not quite true. Before Mopar came out with the slant six 727 trans, they used an adapter to allow the use of a small block 727. This required the used of the "low" starter position. These systems were used in trucks, vans, and "fleet" cars. Most cars did use the high starter with the 904 trans.
If the starter is above the oil pan rail, it is a high starter. If below the oil pan rail, it is a low starter. This is true whether car, truck, or van.
PS: "fleet" meaning some taxi, police, or any heavy duty application.
PPS: In truck use with standard shift, if using the "truck" trans (cast iron bell housing, and shifter coming out of the top of the trans) it is low starter. If using a trans with a shifter that mounts to the tail housing, and has linkage, (could be cast iron or aluminum bellhousing) it would be high starter.
