408 Build help

That Mopar crank is a Scat product - good for 600hp+. The rods I'm not familiar with but any factory type rod using a rod bolt and nut will need the bores notched to clear it. Not a big deal but figure it into the work because you'll have to mock it up, grind it away, then take it apart and clean everything prior to fianl assembly.
Dished pistons are what you want. Who made them and what are the part number?
The iron heads are fine, and using the dished pistons will mean great on any pump fuel. Have them redone by a real performance shop and upgrade the valves to 2.02/1.65s along with a 5 angle valve job and gasket matching. Have the guides cut down and the spring seats cut while they're at it.
A tried-and-true low maintenance cam is the Crane H-302-2. It runs very well in that combo and will clear 425hp with ease if the heads are any good. Run a set of adjustable 273 rockers (or any iron adjustables) and you're good.