302 Holley 4 bbl auto. Starts easy, idles good. After it warms up, it starts to idle a little rough and will cough going up a steep hill. Nothing I can't live with, but would like to fix it.

 

There should be a power valve behind the (I believe the rear) metering block and if the vacuum passage is blocked or the power valve isn't working that could produce the symptoms you are getting. Possibly the performance is satisfactory while the choke is not fully open, but once warmed up it may be starving for fuel on long acceleration.
Also the float level could be a little low and if I recall correctly the rubber? tip on the float needle used to swell from the unleaded gasoline and caused a slightly lean mixture and power complaint.
I'm sure you remember all this stuff and just need a little reminder.

 

I went to carb school in the 70s, but that's been a long time ago.