Brutal honesty incoming, brace yourselves...

Some time back I replaced the in-tank electric fuel pump with a new one. On the rubber line going from the pump outlet to the steel hardline of the pump stalk, there was a brown plastic(?) piece that looked to me like a recirculation valve. It looks like this:

Photo Credit - Youtube/LegacyNorthWest

Figuring it was just a recirculation valve & that it was seemingly not functional, I didn't reinstall it, instead just putting a rubber fuel line in place. Whelp, I'm here to say that I was wrong.
What this item actually is, is a combination recirculation valve (intended to help keep the gas cool in your tank), but also a fuel check valve. It's intended to keep fuel in your feed line going to your carb.
Why is that important? Well because without that check valve, when you shut your engine off, all the fuel in your feed line drains back to the tank.
Then when you go to start up later, the fuel pump has to refill that fuel line, & the engine won't start until the carb fuel bowl gets filled with gas.
In my case, on cold starts, it would take 4 to 6 seconds of cranking before the engine would start. This is not good for your starter, battery or the fuel pump over the long run.

So if you're replacing one of these fuel pumps, make sure you reinstall that valve right back where it was. And make sure you have it in the line with the correct side up, otherwise it won't allow any gas to flow into your feed line.
I don't remember if that valve has any markings to show fuel flow, and I don't have it anymore to check (dummy me tossed it away).

But I did find a good replacement for it. I found this one on Ebay:


The size shown is correct for 1975 to 1978; I don't know about later models but I would think they are the same. Fuel line check valves need to be installed as close to the tank as possible, so I ended up putting this one in the middle of the rubber line that connects the tank hardline outlet to the hardline that's fastened to the underbody.
Now that I've got that check valve back in the fuel line, cold starts take about 1 second or less of cranking before the engine starts! It's a huge difference.

I whipped up a Youtube video of what I did & if anyone wants to see it, it's here: