The magnum engines don't have provisions for mechanical pumps. Mopar went to electric pumps in 86 or 87, and motors made since about 1988 don't have provisions for mechanical pumps. It would be a major pita to adapt one in. I'd go for an electric pump at the tank if you can't put one inside the tank. The electric pumps are a little more noisy outside the tank, but its easy to get used to. The start problems electric pumps solve is worth any noise they may make.

I haven't run a mechanical pump on anything for 15 years or more. In all that time, I had 1 electric pump fail when I got into crappy gas once. For several years after that, I carried a spare electric pump. The only times I used the spares was when someone we were traveling with had mechanical pumps fail. Gene