is it a donut joint, or flat flanges? if they're flat, then there should have been a gasket of some sort there. And no, foil and tape isn't going to cut it. Exhaust gaskets are typically metallic.

When it comes time to choose the exhaust for your project carit's important that you consider needs over wants. Admit it, you want a 3-inch exhaust, you want long tube headers, you want stainless. But ...