Crazy Backfiring

[roysgreenstang]

yes the gears were set to 0 degrees. And yes they are adjustable, 4 degrees advanced or retarded. I just got the OEM length pushrods for a mustang, hardened steel. I compared them to the pushrods i took out of the engine and they were idintical. But also when i changed the pushrods i also changed the heads. Im not sure if those are exactly the right length pushrods for the new set up, but would that cause this outlandish backfire. Also the rockers were adjusted as per the books recomendation. The recommendation was and i dont remember the order and im in afghanistan right now so i cant check but it was 6 valves at #1 tdc not sure exactly which ones, turn the crank 360 six or four more valves turn 180 or 90 cant remember and then adjust the rest. I also adjusted, after that didnt working, use the 90 degree method. Start with # 1 Cylinder and tdc 0 degrees on the crank, adjust that, then 90 degree turn, #3 cylinder, then 90 degrees, etc. through the entire firing order, none of which worked for me. I heard that not having the proper length pushrod only affects the geometry of the engine making the valve guides wear a little sooner then they are suppose to but not affecting the engine performance as long as the rockers are adjusted correct. As for the adjustment, i would turn the adjusting polylock nut until the pushrod had drag when spinning it with my fingers then a quarter turn more. This is the only way i was told to adjust these rockers, in the book and by other people. If that helps, i hope to here your opinion on the matter, and thanks for the help. And if im wrong about the pushrod length and it not affecting the engine if the rockers are adjusted properly then please tell me. I dont know what i would do with her being on the road this year.