stinky super six?

alright i put the super six setup on the duster. it runs real good. has decent power for what it is. motor is all stock, with the exception of the super six, and gasket matched exhaust manifold with the outlet opened up and 2 1/2" full exhaust. i have the timing at 2* initial. it stinks at idle. idles smooth, but pretty stinky. i rebuilt the carb but to be honest i really dont remember much for internal adjustments or jets or what it had going on. last 2 tanks ive checked and im getting 17 mpg to the tank with 2.7 gears. combined highway and city driving. doesnt seem too bad but i think it should get better. all smog equipment for 74 is in place, and seems to be working. car runs good and drives good.