Can I hook mech fuel pump on same line that electric pump is on? Will it pull fuel or do I need to do the bypass style pressure regulator?

 

If you use a mechanical pump with a return line, you can use it and the in-tank electric will become a "pusher" pump.

If the mechanical doesn't have a return line, you need to put a return-style regulator between the mechanical pump and the carb. The electric will still be the "pusher" pump.

Either way, you need a return to the tank if you keep the in-tank electric pump.

 

Even if I unhook the wires to the electric? Can the mech pump suck fuel out or will it suck air? I'm trying not to have to run the return line.

 

Maybe, maybe not. Do you feel lucky? Most likely, it will be "not", then.

Either use the in-tank electric, or drop the tank and remove it. The "door #3" option is doing the job half-way.

The car already has a return line. Using it helps prevent vapor lock. In other words, it's a good thing. Why not use it? The in-tank pusher is about as 100% sure to prevent vapor lock as you can get in our cars. Pretty good insurance.

 

Thank you, I was not aware that the return line was already there, all I'd need is the bypass regulator