is it worth the effort? (cam)

Agreed, keep the internals you have and look at other stuff. Maybe try a bigger carb, and what kind of headers and exhaust are you running?

I'm doing a Magnum build with stock pistons and from searching around here you'd be pushing it really close with piston-valve clearance going up to a cam with that much duration and lift. Biggest i've seen mentioned that works with a stock shortblock is around 224-226° at .050" with around .550" lift which is what i'm running (custom grind from Racer Brown).