What Jerry said in this answer and the previous;
EXTERNALLY Balanced Meaning,the balancer AND flywheel matches that crank.
So be careful if you do a clutch job and resurface the flywheel.
Along the other side,That truck,if it,s a fact.4 spd an SM465
Dead telltale for a SM420,when reverse pulled TO you on the stick and then back toward the seat.
SM465 push the stick AWAY and back to the seat.
Great find and good luck with it!
Regards Steve sr.
