I ran Mallorys for years and its a good distributor. Try and get it on a dist machine and set the dwell. Remember 3K on the machine equals 6K on the engine. If I remember right dwell should be around 35, a lot more accurate than point gap. Also the machine will show if your getting point bounce which could occur, I just bent the springs out to add a little more tension when I put a set in. I've heard of the dist cam lobe wearing down and causing a problem but I've never seen it, thats why they give you that little pill full of grease when you get new points, to grease the cam lobes.