Got the following note from my mechanic the motor is a 1974 2.0 single carburetor

"The non-vacuum distributor was binding, so I took the top plate off. I found a couple of loose washers in there - no idea where they came from, but they're out. Question for the group. Notice the spring? Generally there are two. The vacuum advance has two. But, with non-advance, one may be the norm. That's the question. One or two springs on a manual advance distributor? ".

Hope someone with more knowledge and experience can help. Thanks!

You need the 2 otherwise your advance with be too rapid,this will provide a poor driving car.
You can see the posts there for the second spring.
Many years ago the VW drag race guys would remove one spring for a rapid advance which for that purpose was great ...in a street car it sucks.
Good luck finding a spring

That dizzy is busted baby, there are repair kits for certain Bosch units but this one is not worth it to fix.
Cheepy 009 will replace it, add a Pertronix it will run better.
Stock FI has 2 springs different lengths.
Not sure about that unit you have.
As porschetub said it could a performance mod, but with a single carb?