I have a 56 Plaza with the straight 6 motor with the single barrel. Is there anyway to switch this to a different carb? Or is there a rebuild kit that holds? This carb has been rebuilt twice, and for the first little bit its great. Now there is a stumble from a dead stop, again. Anyway to switch to a 2bbl holley or even rochester? Any other carb switch over? Thanks

If it's stumbling, you are probably loosing the Acc. pump.
Common issues are scratches in the bore (carefully polish them out) or the check valve is not holding. That depends on the type, but dirt will cause it. Make sure the filter is catching all the junk. If it's a ball and seat, get a new ball. Using the old ball and a punch, carefully tap the old ball into the seat to make the seat smooth. If it is a diaphragm, they often develop leaks. If it is also a diaphragm valve, there isn't much to do aside from clean fuel.

I believe I read someplace that the 1bbl from a slant 6 bolts up in place of the original flathead carb. To install a 2bbl carb, your going to have to modify the carb mounting base or buy an adaptor, if such a thing exists. Gene

You can even run two

And finally, there is a factory two barrel intake for the Dodge/Plymouth flathead six. It was standard equipment (I believe) on 56 Dodges, optional on 56 Plymouths. Maybe other years, too. Kinda hard to find, though.

Really appreciate all the help guys. Looks like I have some work to do this weekend.

I rebuilt the carb on my 57 using a kit from Daytona. That's been about 7 years, and it still works well.