Length of clutch fork?

That is for a mechanical clutch linkage on the driver side?

Have concluded that my engine, bell housing, transmission, etc. are similar to what would have been factory issue on a Dodge D600 medium duty truck, with hydraulic clutch, with ball end of a 13" fork on the right (passenger) side.

Literature for that suggests clutch was 12" standard or 13" optional. So what it seems I've got is someone replaced the hydraulic clutch with a mechanical cable system, using a 11" fork on a larger than standard clutch. Might explain why it seems "stiff".

BTW, same literature also describes the engine as a "premium 318" putting out 212 hp. Curious to know if the "premium 318" was just a standard 318 engine, or if it is somehow different.