Im depressed

Hello all
I purchased my 440 Dart back in late October, I knew it needed alot of front end and brake work. I really did not drive the car anywhere except across the street as I did not have insurance on it. Anyway over the winter as time permitted I replaced every front end component, had the steering box overhauled by firm feel, new champion radiator, new 750 holley carb, new brakes, calipers, master cylinder, braided steel brake lines.
I just finished yesterday getting the car back together, got the insurance, now I only need to get it registered.
So I decide to drive around the block a few times, my first to second shift is close to 3000 rpm, and very very hard, I dont know the speed as the speedo is inop, Second to third never came, I accelerated to close to 4000 rpm no shift to 3rd.
Im upset that I may have to rebuild the trans. The car has 4:56 gears
Could it be that this transmission really needs to get up there before it shifts to third? I think I was at least 40 mph or more and there was no shift to 3rd
I really want to start driving the car around
Perhaps I should have put this in the transmission forum, but is there anything I can do adjustment wise to get a shift?

thank you
George G