CUTLASS New noise from olds 307 ticking/knocking/exhaust leak?

Tz44

Tz44

Not-quite-so-new-guy
Mar 24, 2012
47
8
Recently bought an 86 cutlass and noticed today on the way to work I have a sound when accelerating. At idle all I can hear is a belt/accessory squeak but as I accelerate or rev the engine quickly there’s a loud tapping sound. I tried to isolate it with the hood popped but haven’t had much luck.
If I pull the throttle back slowly I don’t really hear it. The exhaust is in bad shape under the car. Dozens of holes in the intermediate pipe. I can’t get a good look at the manifolds to see what kind of shape they’re in.
It sounds a lot more like a tap than a knock to me but I’m no expert. Thinking it could be valvetrain...
I have a video with the hood popped while I’m checking it but couldn’t figure out how to load it here. I’d appreciate any suggestions on how to figure it out.
 
Tz44

Tz44

Not-quite-so-new-guy
Mar 24, 2012
47
8
I took the exhaust off behind the catalytic converter and still have the noise. I got under the car to see if I could find any other holes in the crossover pipe or manifolds but wasn’t able to find any. Still digging, just wanted to post an update.
 
Tz44

Tz44

Not-quite-so-new-guy
Mar 24, 2012
47
8
It still has all the stock emissions parts on it. Does any of the AIR stuff tend to leak?
 
blk7gxn

blk7gxn

G-Body Guru
Feb 7, 2019
968
93
Too, with those, the 307 with OD, cruising down the highway it may sound ok and once it pops into overdrive, the "tick" should be MOST prevalent if its the exhaust. Usually a "knock" would get worse when the motor is NOT under load such as in OD. But like the others said, id eliminate the exhaust issue first, its the cheapest
 

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