Re: changing pool pump cord
The EASIEST way would be to exchange the pump for one with the twist to lock plug on it. Above ground pumps can be ordered each way. Some localities require the twist to lock plugs for code requirements so manufacturers supply the same model pumps in both configurations. As far as changing the power cord vs. the recepticle, it's probably easier to change the recepticle than a manufacturer attached power cord. Be sure to shut off the circuit breaker before you start and make sure there is no power to the recepticle by using a meter! If you are not really sure what you are doing get an electrician to do it. It's a fast and easy thing to do.
Re: changing pool pump cord
OTOH, in-ground pumps usually don't come with the cord and it has to be installed. Mine did and it DEFINITELY has the twist-lock--because it is a 220 volt pump!
If your pump is 110, and your outlet is 220, you can't do this. But, if your pump can also be wired for 220, (it's in the manual) you would do much better to replace the cord with a twist-lock assuming the outlet turns out to be 220. If you have the choice on your pump's motor, 220 runs cooler and more efficiently and your bill will be lower while your pump motor runs for more years.
But be careful: There are a number of different 220 twist-lock plugs depending on the amperage draw (and, also remember that 20amps at 110 translates to 10amps at 220. Why? Watts = Volts x Amps and that's always and forever. Double the volts and to get the same wattage you halve the amperage. Your pump will draw the same wattage no matter what because the watt is a unit of work.) So....the wattage of the twist lock determines its configuration.
And, of course, the configuration of a 110 twist-lock is different from 220s!
Re: changing pool pump cord
Ingound pumps normally do not come with an attached power cord since they are hardwired into the electrical. Above ground pumps do come with an attached power cord.