Whistling sound coming from the carb, right at tip-in ('71 318, Holley 2 Bbl).

I just put the carb back-on about about two/three days ago, after I put the engine in, but I did think of that. No joy.

Anywhoooo, once she got up to temp and I got all of the fluids topped-off, I thought I'd rev it up/"give her the onions" just a little bit, and I'll be damned if she doesn't make a rattling/clacking noise around 2,000 RPM or so from the front of the engine somewhere. Which makes my heart drop.

My bad, sorry, when I said base gasket,
I meant the screws up thru the bottom of carb, fastening the base to the body of the carb.
If you grab the top of carb and twist back and forth, it'll likely move on the base, the whistle may disappear till you let go .