My red top blem in my 71 is almost 13 years since I put it into service and is starting to get soft, thus I have been having starting issues this winter. Since I have the "non-USA" distributor I also utilize the non-OEM ballast resistor in series with the coil positive lead. What I have been doing lately is jumping directly from the battery + post to the downstream side of the ballast resistor and she starts right up.
But I have also had the heat soak and stuff at high altitudes even with known good OEM pumps. Both on my 40s and my 60.
To speak to the original question, it is probably not harmful to put a mild electric pump upstream from the mechanical pump, just make sure that it isn't made for MPI, which uses a much higher pressure than TBI. My daughter's 60 had an electric in it when she bought it, it crapped out pretty quick. She got some Autozone generic replacement and it would put out so much pressure that it would stick her bowl needle and cause starvation. When we ditched it and put in an OEM mechanical everything started working like the factory intended.