my understanding when I was putting my 360 together is all cranks are the same
the freeze plugs ARE a press fit but a little sealer doesnt hurt but not silicone sealer (i use form a gasket the black gooey stuff for frost plugs)
yes do the valves to 2.02 and 1.60 if you can afford it
several companies make shorty headers ...headman is my recomendation
if you have a edelbrock performer why go back to the stock 4bbl manifold? I have one if you really feel the need . No TQ tho.
sounds like your on track to make power (torque ) with your truck ...make it breathe and the rest will follow has always been my philosophy when making a engine for someone who wasn't racing