it doesn't, you can still hear it, sounds like an exhaust leak to me. Does the car shake? are the pressures and temps good? Does it become worse with rpm? What weight oil are you running?

 

yes sir i know u can srill hear it car was not fully warmed up i was freezing my nads off car was about half way to norm operating temp car seems to run and operate fine nothing running hot and oil press is fine i have owned car for three weeks when i got car i changed oil and coolnt (with thermo) thermo was bad (cheap auto parts brand) went to ford boght motorcraft thermo no problems car did not overheat or even reallt get that hot just was bove norm about 3/4 on gauge car had x pipe that crossed under trans and hit everything on road including my drave way so replaced x pipe with h pipe i also installed a rev hanger delete so rpms fall instead of hang after all this is when i noticed this prob car no longer has high idle and its also about 20 degrees colder than whats its been i swear it sounds like its coming from fly wheel

 

no car does not shake and 5 w 30 castrol syntech

 

my $ is on an exhaust leak, tighten the connection to the mid pipe, mine used to have a few issues with the bolts lossening with expansion... put the heman grip on it, there is no gasket it is meant to be sealed by clamping force

 

have you ever ran it on low oil because thats deffinently your rod bearing, my 99 cobra dont that and threw a rod.

 

Well my header bolts used to back out all the time and you'd hear this real faint ticking during acceleration, which was pretty scary at first. I thought for sure it was head tick on my Cobra...anyways, it would go away sometimes after the car warmed up and things expanded a bit, but it's a pain to tighten the header bolts. It's hard to tell from a video...but I'm not actually thinking it's an exhaust leak. To me, it sounds too hard and well "knocky" to be just an exhaust leak, unless it's a major one.

Recently, I heard that sound, a deep low knock upon startup that would seemingly go away with time, but low and behold (thanks to some silent detonation) I had blown a piston. At first, yeah I thought it was just those dang header bolts backing out, but as time went on and I made the mistake of driving the sound got worse (as did the damage). Low end knocks tend to sound pretty similar (at least to untrained ear or on a video), so it's hard for me to say hey that's a thrown rod, blown piston, rod bearing, piston slap, etc...but I think it's internal. Anyways, now my engines being rebuilt, but it's all good, we're going forged internals and I can put in those Stage 8 Locking Header Bolts to stop those exhaust leaks.

I'd put my money on something in bottom end...have it checked out by a mechanic to be on the safe side, but I wouldn't drive it much until you've had someone professional say for sure that's just an exhaust leak or that's normal for whatever reason. You'd hate to one morning just be on the road and the engine sieze up.