Have been using a the 6 volt version of that Carter fuel pump (4259) for about 9 years now, and it has been working well. At 6 psi, it does not overpower the needle and seat in my Zenith carburetor.
PumpAs mentioned, make sure to use a pre-pump filter. I am currently running this one, made by Holley. It filters down to 100 microns, so it will keep the bad stuff out of the pump, but not cause too much of a restriction.
FilterIt is a little pricey, but it is well made and you can disassemble it to clean it - so it will be the last one you will ever buy. I converted the truck's frame mounted filter to pleated paper, to trap the small debris before it hits the carburetor.
I still have the mechanical fuel pump on the engine, but it is non functional and is just there to simplify fuel line connections. The insides have been gutted and a block out plate and gasket have been installed between the two halves.
As also mentioned, for safety, you should ALWAYS install some type of pump cutoff circuit, to ensure the pump stops whenever the engine is not running.
Best Regards...