Small hiss/pop from right side followed by a strange type of exhaust stench.

[doubletee]

Could that be caused by a failure of the intake o-rings? It seems to happen most around 2000 rpm - 2500 rpm when just putting along at slow speeds (unless it's also happening at higher speeds and I just can't hear it). It also seems to stop, or at least happen much less frequently, after the engine reaches operating temp. Exhaust header nuts are tight. Any other thoughts? Thanks!

[Highbinder]

Usually if the O rings are leaking you get a popping sound out of the exhaust when letting off the throttle and there are stains around the seal that is leaking on top of the head.....you may have a vaccum leak so check the lines, the #6, last cyclinder on the left side to your right, has a vaccum line that goes up to your fuel valve, check that also....don't tighten those exhaust nuts too much, they are only suppose to have 9 lbs of torque, you don't want to break off one of those studs the next time you let the exhaust down....good luck ...

[doubletee]

Thanks, Highbinder!   

I have already replaced the vac line from #6 to the petcock. The other two (#3 and #4) are set to be replaced within the next week or so. Don't have any stains around the bottom of the intake tubes, so I'll hope replacing the vac lines and caps will resolve the issue. If not, I'll move on to replacing those seals. One thing at a time!     Thanks for the response!