Manifold exhaust leak?

[S]

Had lifter fail. Replaced top end. Ran truck with no exhaust for about 500 miles with new headers and y pipe. 

 

Threw old exhaust pipe back on for road trip. Noticed a ticking noise right away on start up. Spunded like lifter tap but pulled cover and lifters were all fine. Since they were just replaced. Tappong noise goes along with engine rpm. Get oil/gas smell when fan blows heat unsure if related. 

 

Passenger side is much noisier than driver side. 

 

Sounds like it putters on cold start.

 

Cannot locate issue. Hoping only exhaust leak.  

Thoughts?

[CamGTP]

That is for sure an exhaust leak.

[rlcole321]

I second it!, check header bolts and gasket. Did you keep the AFM system?, did you re-tune after top end replacement?