dash rattle please help

[1972BlueC20]

I know this is a long shot, but my truck has recently developed a rattle noise at certain speed while driving in the dash area. Its driving me crazy. My truck was almost completely rattle and squeak free when I got it....I think my damn exhaust is rattling this truck apart slowly. It's friggin loud (flowmaster 2 chambers dumped)

Anyways.....it sounds like loose pocket change rattling in the ashtray, I did in fact have loose change in the ashtray so I was hoping it was that but nope.

I can't seem to see anything causing it.

Anyone else have a rattle they've tracked down and fixed?

Maybe it will give me some ideas of things to check.

Any help or suggestions are appreciated.

And I know these trucks are old and make noise.....I get it....I like it, but If I can fix an annoying rattle I will....

Thanks,