Make sure you port the heads once the valve seats are opened up . , it will help to radius the entrance to the intake port as the 308 heads use a smaller port window than the intake manifold port .
My preference is to use Forged piston not cast or Hyper , this allows further increases in HP without rebuilding the short block down the road .
Using the stock converter may limit the cam choice , 318/340 do not have a long stroke so torque is limited so getting them into the powerband before the load is applied is critical .
I like Lunati cams for Mopar , the Voodoo series works very well , they are designed to maximize the ramp speeds with the larger diameter lifter used in Mopars , many of Comps cams are designed around the small block Chev with a smaller diameter lifter & just copied onto the Mopar cores . The Chev & Mopar small block are very different engines , the Mopar not only has the wider diameter lifter but the rod ratio is totally different which alters the piston speeds & dwell time so the cam really needs to be very different between the 2 engines . Always check piston to valve clearance .
600 CFM on a bored 318 will be perfect , you will end up with approx 322 CI & you want close to 2x the CI.
The intake is a good choice although even the factory 340 intake is one of the best intakes .
I would use a Melling HP not high volume pump , Billet double row timing chain , you can add the timing chain tensioner available from Mopar , use a windage tray , don't worry about 4 bolt mains it will not need it , balance the rotating assy of course ,
For exhaust I would use the later 92 up Magnum manifolds , these fit well & are some of the best iron manifolds ever used from the factory .
I bet the little 318 will surprise even you ! a 70 318 was rated at 230 HP with a 2bbl , with carb intake cam & exhaust it will make decent power
