More Hp from a RHS 360

I'd lose the intake for starters. What rocker setup do you have? What springs were used on those heads? I would not stick a solid roller in it unless the block was bushed for it. But that's just me. Without block mods I would consider a solid flat tappet, that will make more torque, over a wider rpm curve, and more peak power at a more usable peak rpm. But any larger cam will need matchign springs, and rockers that can handle it. That looks to me like you have stock Magnum type stuff and you're at the limit.