Is the merc flathead distributor any better/different than the Ford version? Can the merc version be used successfully with non oem carbs like the Rochester 2GC?
If you are talking about the 8ba / 8cm dizzy thay both suck. They have no mechanical advance at all. Look up bubba's hotrod shop ( gmcbubba on here ) he can hook you up with a small block chevy dizzy that fits a flathead ( points ) for less than 200 bucks! And it looks like it belongs there to!
There's no such thing as a Merc version. No, you cannot plumb it to a Rochester. The vacuum advance is designed for a special port on the Ford/Holley carburetor. Lose the carburetor--lose the distributor.