Sounds like a good complete tune up with points, plugs, cap, wiring, and filters might be a good place to start. A coil may help. Play close attention to the wiring or any changes that may have been made. You need to determine if you're getting spark when it won't crank.
The spark knock could be timing, advance, or too much of it. A good tune up will correct this if done correctly. Also, it could be heavy deposits in the combustion chamber.
An electric pump will not hurt anything. If it will hang to a long pull on a hill at WOT I doubt if it is the pump. Check the tank and the fuel pickup tube sock.for trash and all fuel lines for rust and the just go ahead and replace the soft lines.