[buzzinhalfdozen]

An MSD ignition will work properly if you ground it with a rusty bolt. From my experience with their systems the only problems with EMI, RFI, electrical noise what ever name you want to give it has no ill effects on any but their Digital systems. You did'nt say if your timing appeared to be correct , which I'm assuming it is. Does the engine exibit black smoke, what do the plugs look like? Do you have good blue spark coming from the coil? If you don't own one I would get a spark tester and an MSD tester and diagnose the problem from the trigger source ( crank trigger or Dist. ) out . There are a multitude of possiblities you must have a logical and strategic approach which means you have to see what isn't the problem then eliminate down to the actual cause. Looking at the plus and for signs of black or gray smoke can be some tell tale signs. Unfortunately the new BUZZ words today for any mysterious missfire is always interference, RFI, EMI , back feed I've heard them all in 25 years of repairing cars and racing them I've yet to find any of them to be a problem. Good luck and please let us know how you're progressing. Joe