Msd can style coils are a waste of space. They cost more, don't do anything better, and don't even "help" a cdi box.
Ask msd why your power didn't change and they'll tell you that they're stock replacement, but if you ask if it's a stock replacement they'll tell you it's made for racing. They do the same crap with late model COP coils too, and in most cases the msd ones are horrible quality compared to OEM yet cost 3x more. Go figure. If you ask why they burn out so often, they'll give you the "made for racing" excuse. If they don't make more power they're "stock replacement".
I'd run an OEM coil, given the choice. But finding them new isn't easy anymore. That or go with any number of good aftermarket systems, from FBO to AN HEI conversion.
