Just received my new vacuum fuel pump. I see there are two openings on the vacuum part. One for the windshield wipers. The only other vacuum hookup is the distributer vacuum advance, but I thought that needed to go directly to the carb. So, what's the second threaded opening for on the vacuum section of the fuel pump?

Thanks!

The other opening goes to the place where your wipers originally hooked in to the manifold, That way you can get vacuum to the wipers either from the fuel-vacuum pump or from the manifold. There is a good explanation at the K. Hardy web site 49 -53 shop manual. Here is the link to the page in the manual for the fuel pump:
Fuel & vacuum pump

Thanks Mr. Mack. So, let's make sure I understand correctly. Using the picture in the link you provided - I disconnect the wiper motor vacuum hose from the manifold and connect it to fuel pump vacuum inlet port (#29). I then connect the fuel pump outlet port (#16) to the manifold where I disconnected the wiper motor.

Did I get it right?

You were right and I was Wrong Wrong wrong!

It is just the opposite, after reading the book!
OUTLET goes to Manifold
INLET goes to wiper motor!

Go the bottom of that page and click on ;next page; and there is more info. about troubleshooting and maintenance, also explains where the hoses are connected. I hope this is helpful.