Just a FYI for anyone out there looking for a Hood Tach or having issues with MSD, I contacted Randy at RC Tach Shop from the info Harold gave me and ended up ordering a new 68 Tach from him and he assured me it would work with MSD. Received it in mail, had it painted, hooked it up and everything worked perfect, no adapters needed! Thanks for the info Harold!
The Tachs he builds are the higher priced ones Ames sells and really seem like a nice setup. Sealed up real nice, and according to a RPM calculator I found online and the rear end I have, its reading spot on!!