This is my first post here and it's not going to be my last. I am just trying to set the points gap in my dads Mallory dual point dizzy. Can anybody reccomend what the point gap should be?

Thanks in advance.

Welcome to the site!

Unless there’s a tag on the outside of the Mallory distributor saying otherwise, for an eight cylinder eight lobe Mallory distributor set each breaker point gap setting at 0.018”.  If using a dwell meter, then only re-adjust the breaker point set that opens first to make total time dwell adjustments.  Total dwell for this particular application when checking it with a dwell meter should be ~34° +/- 2°.  Unless you are readjusting the set of points that opens second, the ignition timing itself is not expected to change.  But to be on the safe side, be sure to double check the ignition timing anytime point gaps are being fiddled with.