Hello, my first post. I have an old MSD-MC1 (PN 4220) system that is failing, after 25 years of great service. The engine will run fine at low load and RPM, but when loaded at higher RPM the system will not run properly and the RPM decays. If I revert to the stock ignition system, there are no problems, so I think the fueling is OK. I'm using Moroso Blue MAX 8.0mm Spiral Core HT lead and their resistance is within the Moroso guidance of 800 Ohms per foot length. I suspect the MC1 CDI Amplifier is failing. Could you recommend a suitable MSD alternative system (With wiring as Close to the MC1-4220 as possible) from the current lineup so I can easily replace the failed unit. Any help or guidance would be appreciated. Thanks, Dan