Is there a big difference between the 911 fuel pump (580960009) and the 914/4 fuel pump (580960011) ?

If the 911 fuel pump is for a CIS motor, the difference would be pressure. The CIS pump will put out about 75 psig and the 914 pump puts out about 40 psig.

Since you have a fuel pressure regulator in line, it won't make a shit worth of difference to the engine.

Thanks for the info. I just ordered one from EIS and I didn't notice the different part number until I compared it to mine. I looks identical. Hopefully it doesn't strain my pressure regulator.

I'd be very worried with the plastic and aged rubber fuel lines handling 75 psi. If you decide to go thru with this, make sure you have a fire extinguisher on the ready!

If aged 914/6 fuel lines can handle it, i'm sure that the 914/4 will be no different. I hope.

All 914/6 were Weber carbureted and the pump ran about 3.5 PSI.
This will not be enough pressure to run any 914/4 fuel injection...

The part number for the 911 fuel pump and the 914/6 fuel pump is the same (580960009). I guess it can handle it.

While there is a 'the' 914/6 pump, there is not a 'the' 911 pump. There's almost 50 years of 911 production. The very early cars actually had mechanical pumps...

So yes - 'the' 914/6 pump has an equivalent 911 pump.

But that's not the point.

The point is - are you trying to run a 914/6 with Webers with that pump, or not?
You haven't said what kind of 'the' 914 you've got... (It makes a difference...)

Yes I will trade you for the proper pump

I think I bought the wrong pump. I bought a 914/6 pump, however, I have a 914/4 1.7 with Fuel Injection. It's not going to work.