If you decide to use the LA rocker shaft type heads, be sure to check and see that the oil passages for the heads are open to the cam journals, if not - then you need to have new cam bearings installed which have the oiling holes lined up properly.
The motor is setup to accept hyd roller tappets from what I can see. What you need to install these should you choose to do so: The spring steel spider that bolts onto the valley bosses, 8 lifter retainers and of course the correct length pushrods and stock roller lifters.
Its not a bad idea to consider going the roller cam route. I did it on my commando 360 crate motor - runs really nice - lots of torque. When I did my motor nobody was making what I considered a good roller cam for mopar engines - I had comp cams send me their roller profiles and picked my own lobes etc.
Should be no issue running a hydraulic flat tappet cam as long as you have oil passages to each tappet bore.