Brian, I suppose you have tried to deal with the 28, rebuild etc? I think you are supposed to have a 30mm carb to begin with. 67 right ? Does the gov. work ? I think you can use the gov. but you might have to change some studs . Been to long can't remember. If you don't use the gov. you will have to use a spacer I belive to keep the carb accel. pump housing from hitting the gen. If the gov. does not work, you could gut the thing and use the housing for a spacer.