I gotta motor noise...HELP...Please

[784X4GUY]

Alright yall,

My motor developed a popping noise around the number 7 cylinder. Thought it was a header gasket replaced it to no avail...So i thought my cam was going out so i replaced the cam,timing chain,lifters,pushrods,but left the stock rockers on it. Ive got the lifters adjusted right. I know its not that. But its still making that sound...Oh by the way as the motor is running it is popping and if you let it run long enough it will blow the gasket out at the number 7 cylinder. Oh if you hit the gas hard you can really hear the pop but if you ease the throttle to like 3000 or 3500 and hold it there the sound dies down a lil bit...please any help would be greatly appreciated...Oh also ive had the heads off and took them to a machinist and he pressure checked the valves to see if they were seating right and they were all perfect...he also checked for loose studs,broke springs and such but everything was good...please any help would be appreciated