I notice what sounds like an exhaust leak when I drive my 56 Fairlane with 292. I changed to a 57 B manifold and Autolite carb and it runs good but I hear a pfft pfft pfft when driving it. I don't hear it idling nor when I rev it at a stop. I checked for loose bolts and tightened the few I found but no change. I even plugged the heat line to the choke but no luck. I haven't seen any signs of exhaust soot around the intake nor at the exhaust manifolds. For something so seemingly simple it has me stumped.
Any suggestions where I should concentrate my search? I don't recall hearing the leak when I had the original intake and carb.


~DJ~ AKA "Bleach"
1956 Ford Fairlane Town Sedan 30K original miles