What about the carb. If its rich or lean it can make it run flat at low rpms. Do you get black smoke out of it when you punch it. Should see a little if its properly rich.
430 gears are a good jump from 373. 411/410 would be good bump up if its right and working well.
Sounds like you got it pretty close just needs final tuning. Build seems to be close to what you need for good bracket/street car. I know others have said cam and cr all wrong but its not that far off from what everyone else is running just needs to be tuned and tweaked.
Checking to make sure the cam is at 0 is a good idea but not easy so I would skip it for now. Play with the timing a little and make sure the accelerater pump is set to its strongest setting.
Does the engine lope badly in gear. Usally if the cam is too big it will lope while your driving down the street below 3K rpm. If its smooth it probably just needs tuning.
Sometimes its best to bite the bullet and take it to a speed shop for Dyno tuning with EGT and wideband. You can play with it for a month and one day at the shop will sort it all out. On the dyno a proper tuner can tell if its rich lean too much timing or not enough. they will need to weld in egt sensors into the headers. Its no big deal doesnt effect performance but does effect the cost of the runs. Only take it to someone you know is good.
I recommend dyno because your build is running and driving. Sounds like you built the engine right. Other are saying they could have helped but you didnt miss the mark at all it just needs some real deal tuner to sort it out for you. CR may be high but you didnt say what the car was used for so it may be right on the money for bracket car.
Also does it knock if the timing is set above 32?