I posted the below on a Power Wagon forum, but I'm adding the Pertronix to my M715's so I'll post it here as well. The Pertronix part number is the same for the M715's and the M37's.

I ordered an electronic ignition for my M-37. This morning I just received and installed my 24-volt Pertronix Ignitor electronic ignition and I am now a true believer. For the $157.89 I spent to have it delivered and the 20 minutes it took to install, this product is awesome. My problem had been the engine missing at high RPM's. I had adjusted the gap, dwell and timing to specs as well as done vacuum and compression checks. They were all within their respective ranges, but did not solve my problem. Once I installed the Pertronix, problem solved. In hindsight, it seems to have been the points bouncing off the cam lobes at high RPM's. The part number is MV-161 and I ordered it from their website. They do not stock it, so it takes 1-2 weeks for them to make it and ship it. All I had to do is trim the two wires, and crimp on the connectors and it all fit neatly inside my stock distributor.

Some comments I received from Charles Talbert at mseriesrebuild.com regarding this post that might pertain to your upgrade:

"Your issue is very likely that the shaft bushings are worn allowing the shaft to bounce around instead of running true. The symptoms you describe are very typical. You should have taken care of this issue by repairing at the time of the module install. If you don't attend to this issue, the pick up ring will soon start to run into the module as a result of shaft wobble destroying the new components. New bushings need to be installed & reamed to .501" ID for top performance. Your shaft may be worn out of spec & require replacement also. End play is shim adjustable. The cam on the top end of the shaft wears & is a major contributor to this. It is repairable only by machine work. The felt under the rotor needs to be oiled regularly to prevent cam wear. Only the bottom shaft bushing gets oiled from the engine. The top bushing must be manually oiled regularly. The top oil seal also is a big factor in lubrication. Many owners are not aware of this, thus we see lots of wallowed out top bushings."