Help me build my 340

Hello all,

I am going to be building a 340 for my 1970 Duster over the winter. I recently bought some more parts on the board from another member, but what I have as of now:

'70 340 block already 0.030" over (may clean up or go to .040")
340 Forged Crank
Kevko Oil Pan
Edelbrock 6077 Heads
Crane Gold Roller Rockers
Mopar M1 Single Plane Intake
Custom Comp Cam Hyd Roller Cam 242/248 @ .050, .540/.540
Milodon Gear Drive
Oil Pump Drive W/Bronze Gear
ARP head bolts
Felpro 1008 Head Gaskets
Mr. Gasket Cam install gasket set

I was also planning on adding:
K1 Connecting rods
Forged Pistons at zero deck (will deck block)
ARP main studs (is hughes girdle worth it)
Quick Fuel Double Pumper (not sure if i want 650, 750, annular, or standard)

Car is a 1970 Duster, 4-speed, 3.23:1 gears and 225-60/15 tires.

I was thinking that the cam I have is too big (would still like a roller cam, maybe like an XE280HR), that I don't need the gear drive, and that I would be better served by an air gap intake. Also, I'm worried that the edelbrock valve springs might not be very good and that I would like to change to beehive (looks like there are several brands that go right on the edelbrock heads).

Looking to get a target of 425-450hp, streetable engine, turns some RPMs since its fun with a 4-speed.

Thanks for the help.