I don’t think it’s that much of a RPM drop and no cam covers that range in a way you could call good. Also, 3K isn’t screaming. You’re just used to new rides that cruise at 70 mph @ 1500 rpm. That’s todays rpm. Yesteryears rpm was an easy 2500 - 3000.
If you’re thinking 3.23’s, your (yet unknown) tire size has a play in a camshaft selection. You said you don’t care about mileage but do not want to travel at 3K rpm. OK….
Your first gear, 3.09 X 3.23 = 9.98 (Excellent for hot rods)
In overdrive, .73 (?) X 3.23 = 2.35 (Not so good for hot rods)
The problem here is a hot rod cam takes advantage and feels best with the first gear final ratio while the OD ratio is so high it’s stifling power and mileage. And the flip side of a small cam….
You get the idea.
If I suggest a cam to try and bridge both the ability to help provide power on take off and be reasonable enough for decent mileage, it can not really be done very well. I know you said you don’t care but here’s the rub, mileage will tank with to large of a cam, a small cam cuts power turning the first gear take off power to a crappy level. A cam between 210 - 218 @050 is what I’d look at myself.
With the Purple cam you have now, I’d use that and tune that carb to be a lean runner on cruise. Fatten the secondary side as needed. Just send it. It’ll be fine enough.
The thing with the OD transmission is the 1-2 & the 3-OD shift has a big drop. You’ll have to rev the engine a bit higher and call it normal. That is just simply how it is going to be. IMO, you can try really hard from here to get the perfect set up with one of the most difficult transmissions and be upset or just not worry about it. You’ll never get to a modern day level, the car lacks all of the equipment that makes it possible except cubic inches and probably a very reasonable car weight.
The old tech is limited. Even if you try and band aid the cam with Rhodes lifters, grab more lift with 1.6 rockers, use new heads custom ported to take advantage of the cam and in the direction you want, it’ll never get to the new car point where you have great power and a double OD for great V8 mileage. Just do the best you can and enjoy it.