Max effort cam for low comp 318

You said you’d be willing to pull the heads so why not start there? Pull em and mill em and get the thinnest head gaskets you can. MLS comes to mind, they’ll make whatever you want. Seems you could get another point of compression doing so. Then mock up the valvetrain and measure piston to valve clearance, then pick your cam. I will also sugggest calling someone who will grind you a custom cam, Jones cams would be my first call.