Bought a used rebuilt carb from another member to replace the misbehaving one on my 68. Problem is it decodes to be a 72 model. So now, wondering if there is a good solution to make it work correctly because the bases, manifolds, and gaskets are different. The 68 has heat passages and a specific gasket that connects to them. It then has a heat shield/shim that goes between the gasket and the carb base. The 70 up models do not appear to have heat passages from the manifold or the steel shim. Anyone know what my options are? So far all I can think is to put the 70-75 gasket with no shim and hope I get no problems from the heat passage, or to use the 68 gasket, steel shim, and then the 70 up gasket on top of the shim. I am in Florida so it never gets all that cold here to worry about heating the base of the carb.