JMess73,
It does sound like your engine is having trouble drawing fuel. A low fuel draw can often be traced to leaks in the overall system reducing the overall ability of the carburetor's venturi to draw fuel. Some things to check are the seal of the carb to the crankcase, you might need to seal it with clear silicon; also Magnums often leak through the o-ring seal on the carb and you may have to put a piece of fuel tubing over the needle to get it to seal properly; the seal of the fuel tank is also something to check you need to make sure it is not leaking which you can check by pressurizing it and holding the pressurized tank under water to see if it leaks, and finally check the fuel line when the engine is running to see if it has bubbles in it - these would be caused by vibration causing the clunk to jump up into the top of the tank and suck in air.

If all of the above check out ok you might consider some type of pressure feed system. A bubbleless tank like Jett Engineering offers or a pressure bladder would solve your problems. The pressure bladder is the cheapest solution but has a learning curve associated with it plus you will need syringes to fill the bladder. Good luck.