Flexplate or converter? What stall?

We talked about this a bit before, but now I have more info. My current motor, a 318 has a 904 behind it with an internally balanced 2800 stall converter. The motor going in is a 408. There is no flexplate on this motor. I need to buy one obviously, but which one? I called the builders of the motor and the rotating assembly has been balanced. I assume then that I can use my existing converter if I so choose, though I think I want to go with a higher stall. I need advice on what flexplate to buy, and what converter, if any, to buy. Here is what I will have, with the transmission still up in the air. Likely going to change to a 200R4, but may stay with the 904 and go with a Gearvendor overdrive.

408 stroker
1992 magnum block
scat 4" stroke crank
Scat forged i-beam rods
Diamond flat top pistons (11.8:1 compression)
total seal rings
Engine Pro main, rod, Cam bearings
Fluid damper
cloyes double roller timing set
Cometic head gaskets
Edelbrock performer rpm heads (gasket matched w/ light porting)
Smith bros pushrods
Comp 1.5 ratio shaft mount billet roller rockers
comp hydraulic roller lifters
Comp Cam
242/248 Dur@ .050, .3660/.3630 lift @ .050, 112° lobe sep. 549/544 gross valve lift
Comp valve springs, retainers, keepers, locators
ARP head studs
ARP bolts used throughout
melling hv oil pump
Edelbrock Super Victor intake
MSD Pro Billet distributor
bronze dist gear
Taylor wires and looms
New ngk plugs
Edelbrock 800 cfm electric choke carb
Mopar MSD 6 Ignition box
Blaster2 Coil
Adjustable rev limiter
Moroso fabricated aluminum valve covers
Hooker Super Comp headers
2 1/2" exhaust with flowmasters