[Pappyx3!]

Martin,

Is your concern the correct starter to flywheel combo?

Check your starter mounting on the engine block, a lot of Gm blocks were drilled for both the straight and offset starter mounts.

The post from the forum you showed is generally correct. However there are straight mount starters that will fit either tooth count flywheel. Most of these I remember had 3 mounting bolt holes.

Got info on the year of the truck the engine came out of?
Pappyx4!