I recently installed and rebuilt a Carter 2101S to replace the Rochester BC on my '50 235. Used the kit supplied by Jon at The Carburetor Shop. It's a great kit by the way.

The air horns on both carbs appear to be the same size when comparing, but the air cleaner will not tighten on the Carter. It's seated fully on the air horn. I have checked and double checked.

My question, what would be good to use as a spacer so that I can use the original filter? Would cutting a strip of thin sheet aluminum work?

I know it seems like a silly question, but I don't want to add something that may have detrimental side effects that I'm not considering. It's also possible that I'm missing something simple and just don't know it yet. I often found out too late that "I don't know what I don't know"!

Thank you in advance.