yeah i never understand that
the set is like 6 bucks at most for both parts

plus they usually give you.018-.022 for the gap
i always set em at.020" and replace the condenser and those old trucks usually fire right up

remember to disconnect battery negative
and after that short out the points with a screwdriver so you dont get a shock from the coil
turn the engine to get to the apex on one of the little cam lobes in the distributor
(turn the by hand with the battery disconnected- i believe theres a spot to stick a large screwdriver in the top of the bellhousing to slowly turn it by the ring gear)

for how cheap they are
to know theyre good and set right it takes 1 thing out of the equation, theyre worth every penny