[buzzinhalfdozen]

There are 2 things to consider here, first have you tried using a different timing lite, I've used some that just will not work on an MSD ignition system. Second Where do you believe your "noise" is coming from? Every wire that has electrical current running thru it CAN emit noise, the trick it seems is in minimizing it. Before you spend a bunch of time and possibly money, borrow another timing lite and see if you have the same issue, a lot of lites' pickups are extremely sensitive to EMI, most modern wire sets are fairly good at suppressing noise. P.S. most dial back lites seem to be problematic when used on MSD ignition systems especially the digital ones.