The KSB is the round component about the size of a tall shot glass mounted on the drivers side of the injection pump. The early KSB and late KSB do NOT swap, nor do they have the same operating function.
The KSB is used as a cold start aid. It will advance the timing on the engine when cold, and is designed to provide substantial injection timing advance in the low engine rpms so as to improve engine operation / emissions when the engine is stone cold after start-up. When in the engine rpms come up, the substantial timing advance tapers off to a much smaller measure of advance. The KSB does not function after the engine coolant reaches ~160* F.
NOT for trucks WITH wax pumps found on 89-91 NON-INTERCOOLED trucks.
ONLY far left piece in second picture.
Part number: F002D20501 (old part number 0330106018)