ok i got a 68 coupe and i built a 5.0 stock bottom end with a comp 274 cam PRE- production GT-40 Heads ( no work on them) a demon 575 carb manual secondary, blah blah. now i have long tube no name headers with an x-pipe and 2 chamber flows with turn downs. For some reason or another im not getting that high pitched ripping sound through the x pipe like i thought i would. instead i hear like a popping. we have checked timing and valve clearance and went from hotter to colder spark plugs. everything we can think of weve chacked. and the car runs fantastic, its just the "popping" in the exhaust. HAS ANYONE ELSE HAD THIS PROBLEM?????????

 

I have had this problem, but cant really help you... here is a thread i started, maybe it will help...

https://mustangforums.com/m_4456163/...tm.htm#4456163