Thanks Ron, that did the trick.

For those who may come seeking the same information later; assuming
that you're using the original stepped pulleys you'll probably do well
with a Dayco #15300 automotive V-belt. Assuming a 2" pulley on the
motor and the original pulley on the jack shaft, a Dayco #15260 belt
also works well and will allow the belt to slip cleanly when the clutch
is disengaged.