I need help bad!!

Hi guys, now I know this forum is for A bodies but I need help badly. over the winter I started building a 400, its in and ready to go but it's very sluggish. Here's the list of whats done to it:

Mopar 400 (.030 ovr)
Edelbrock 850
1" Moroso spacer
Mopar M1 Intake
Stock heads
Champion Copper Plugs
Crane 1.6 Roller Rocker
Lunati Custom ground flat tappet cam
Lift Int./ext.-(.525)
Dur. @ .50 Int./ext.(235)
Adv. Dur. Int./ext.(264)
Lunati Double Valve Spring
Lunati FT lifters
Cloyes Billet Dbl. Rollr. Time Chain
Mopar HV oil pump
Mopar HV pump drive
KB Pistons
Stock Rods
Factory Forged Crank
MSD 6AL Box
Stock Coil
MSD Pro Billet Dist.
MSD Wires
ARP Bolts (rod/Main)
Headers

So anyway we got this thing all broken in and it sounds amazing, but it's a dog off the line. I have a NP435 trans and in second gear it tries to stall out. We tried adjusting timing(not too sure with this type of dist. yet), adjusted the rockers(.012) and repeated. I'm hoping and praying someone on here could lead me in the right direction. I'm using this motor in my 2WD pulling truck and have a week to have it ready. So if anyone can help It'd be really appreciated. Thanks a bunch! Jon