Header gasket leak repair, K-member is out

I did not think about the cats, I do have them, the JBA high flows.

I was wondering if I had a leak somewhere that was allowing fresh air into the system which would cause that rich fuel to burn (pop) in the exhaust rather than the combustion chamber?

My car used to have a nice clean free rev and at some point, I am not sure when it happened, I started to notice that popping sound when I would rev it in the garage......

R

That is certainly a possibility and may be a reason mine seems to be popping more than it did before this gasket repair.