Finally got it running yesterday. Dang these projects take forever. I bought a rebuilt Holley 4160 - VS 750 CFM. I got the manual choke installed too. Now it will crank and idle even when it's 25F. It idles at about 700 RPMs now too.
So what happened in second gear, you ask? Power, lots of head snapping power. There's no stumble, no bog or anything. It hits hard and keeps right on pulling. It also pulls a few more RPMs on the top end. I think the larger carb is letting the engine breath a little better. Power off the line is great too. Everything hooks up good and runs out hard. I definitely enjoyed some adrenaline last night.
PS: I bought the carb off ebay from musclecarexpress for $169 + shipping. If anyone else is looking for a good deal on a carb, I'd recommend their services.