66 390 exhaust

:banghead: why can't I find exhaust systems for my 66 390?! I've taken my car in for pipes before but no one can seem to mate the stock exh manifold to the pipe flange without the heatriser. I tried replacing the heatriser but they keep cracking, I tried changing the flange; that didn't work. I changed the studs, nope. And I've looked everywhere for headers, but the only ones found were for trucks or fairlanes and alike, all of which will not fit between my shock towers. Am I missing something? I need some options here. HELP!!!!