Rick- I can't tellyou what carb was intended for your 61 engine, but if your carter will bolt on it will work. It sounds as though you have a vacuum leak. Check at the base of the carb and at the intake manifold where it meets the head. It could be many other things as well, but get the tune baselined to stock specs for your engine year, set the timing and idle speed correctly, adjust the idle mixture on the carb and see how it runs. I've spent too much money over the years trying to fix stuff like this without truly knowing where I was to start with.
Devin
