66 valiant no start

The way to test points is electrically. EITHER check that you have a good spark as outlined earlier, or ............if not..........

When they are closed they should be a dead short to ground. So with the cap off, bump engine until points are closed on the "flat" of the points cam. Now turn key to on/ "run" and measure voltage from coil NEG to ground. You should see no more than maybe a volt at worst. BEST is if you have a dwell meter, which often have a "points resistance" scale. Then bump engine so the points are at top of cam and either estimate by eye or by feeler gauge what the gap might be

I DO NOT like to try to clean points if not needed. You can sometimes do more harm than good with various sand paper / etc get grit and so on in there and make it "worse"