What the heck is this noise?

[hobo]

I can't figure out what is going on here:

https://youtu.be/V9t_K7f9QeI

Noise pitch seems to fall as throttle increases. Vacuum hoses checked and all seem to check out. I would think a bearing or belt would rise in pitch with throttle. Any ideas?

[gww]

might get a couple ft. long hose, close to your ear then move around with it to locate source.

[EGroscup]

Certainly sounds like an intake leak to me. I am going to guess intake manifold gasket and/or carb mounting gasket.

[PwrWgnDrvr]

When throttle opens, vacuum decreases, therefore intake leak pitch goes down.
Spray starting fluid around carb base, manifold joints, etc. If it sucks in through a leak, engine rpm changes and you can thereby locate the leak.

[hobo]

When throttle opens, vacuum decreases, therefore intake leak pitch goes down.
Spray starting fluid around carb base, manifold joints, etc. If it sucks in through a leak, engine rpm changes and you can thereby locate the leak.

Thanks, will check. It definitely seems to be coming from that area. I pointed a hose at all the pulleys and it didn't sound like they were culprits.

[hobo]

It was the carb mount gasket. How rare (but how lovely) it is when the fix is $3 and 10 minutes.