Lots of guys in my Cadillac club use an electric pump back by the tank and keep the working mechanical pump installed. The electric pump is used to prime the vehicle after sitting long periods of time or in an emergency (the crummy Chinese fuel pump problems extend to virtually every make and model).
After priming the carb for starting, the electric pump is turned off and the mechanical pumps have no problem pulling fuel through the electric pump during normal operation.
Personally, I have no electric fuel pumps on any of my vehicles. After Then and Now rebuilt the glass bowl pump on the Chevy, I've put thousands of miles on it without a hitch.
Just a reminder to find an electric pump with 4psi max. GM specs 2-4 psi for the 216 engine. My mechanical pump operates at 2.5 psi.
