Name that noise

[IIA]

I've linked a recording of my 1970 IIA. Does anyone know what this squeak could be?

https://drive.google.com/file/d/1Hpkb1bL9-dajhCIWjsV9ZfK9vlXU1g0t/view?usp=share_link

[jimrr]

need more description: are you driving? on highway or gravel? is it at idle inside/outside the garage? have you just completed some repair?
things like that.
Jim

[IIA]

It makes the sound when idling. The recording was made outside my garage. It has been doing this for a long time, but I just caught up with other repairs (gauges, windows) and thought I'd take a shot at this. It otherwise runs well.

[jimrr]

does the frequency of the noise increase with A: engine speed or B: road speed and in what gear(s).

[IIA]

It's hard to tell with all the other usual rumbling but I don't think it does.

[biffidum]

Time to break out some hose as a stethoscope. You should be able to tell if it is coming from the top, bottom, side rear etc... this info will help. My guess would be someone's wallet fell down the back.