hello I have an issue I cant seem to figure out. I have hooker shorties 1 5/8 primes to 3" collectors. off that I have 2.5 inch pipe to 3 inch dynomax bullet mufflers. the issue im hearing is when im only at cruise speed 55-65 mph I get a noise out exhaust that sounds like car is having a lean miss. its not lean cause plugs are slightly black. I have timing at 36 deg all in by 3000 rpm. I have a 2800 stall on a 355 sbc. carb is an edelbrock 1405. I only hear the noise when cruising at them speeds. any other speed below is perfectly fine. what gives? any ideas?

 

anybody