I just got a Westach 30psi fp gauge (electric) and the fuel line hose that connects to the test port on the vp. Will I need to use a needle valve in this setup to dampen the pulses or does the sending unit not pick up the pulses as bad as the mechanical gauge?

 

Welcome to DTR !

You won't need a needle valve with an electric gauge. At least I did not when I had an Autometer.
Needle bounced some +/- 2 psi but never got worse.
RJ

 

I would imagine the same "pulses" that cause problems with mechanical gauges could end up stressing your isolator. (Figuring the isloator is going to read the same bumps and pulses to your gauge, it's absorbing them, right?).

The Napa part # for the commonly used needle is WH6820.