73 455 mods

The filter and ignition is a good start. You can easily bump the compression by going to a thinner head gasket. You can also find some hidden ponies in the carb and timing which at the same time may also solve your pinging problem. The first place I would look would be in the advance springs of the distributor. You may have already swapped these out when you did the MSD upgrade, but if you haven't they may be worn or stuck and aren't giving the engine the timing advance that it needs, which is especially important when you put that hotter cam in. Second, you can adjust the vacuum advance cannister on the distributor by using a small allen wrench. I can't give you any advice on which way to turn. Also, you can adjust your ignition timing by loosening the ditributor hold down clamp and rotating the distributor until you hear pinging, then back it off. That sounds kinda back yard mechanicish but it works. Adjusting the pump shot, adjusting the secondary door opening rate and the fuel mixture settings on the carb will give you an addtional power boost. I know this advice isn't specific but it should point you in the right direction. There's a real good website that a guy with a 68 Riv put up. He's done all kinds of mods and has a lot of detail in his tips. I'll try to hunt it down for you and post it.