I decided to post this as a separate question rather than include this in another member's post as I did last night.
Last night I took apart my fuel bowl on my 1973 Holley 1920 and there was no check ball rolling around in the bowl. I consider that a good sign. The power jet valve lever has both the balls in place. My Walker kit 15519A came with a new check ball. Other than the two balls on the power jet valve lever, where else would a check ball go?

SSD said "Carburetor operation and repair manuals (and some training movies) are posted here for free download. You'll want to install a new float in your rich-running 1920, and make sure the power valve check ball hasn't fallen out of the metering block." I will install a new float. I have two check balls now, but I would like to verify that all balls are there before reassembly. Where else do I look?

I plan to put the carb back together tonight. Other than a good cleaning in carb fluid, I am following the 73 FSM, rather than the #1 through #38 parts numbers per the Walker kit instructions. The FSM and other instructions on this site explain better than a numbering system.

This is my first time to take apart this or any carb.

The other check ball in the metering block is in the slot that is in the circle of the block that goes in front of the accelerator pump diaphram. Its in the slot in the center of the circle. If you look on the bottem of the block, there should be a brass or lead plug holding it in place.

Eric, excellant description. I looked on the back of my metering block and could actually see the ball moving around as I tilted the block back and forth. I could also see the plug at the bottom of the slot which must prevent the ball from falling out of the slot. Thank you.

Your welcome.

the wonderful online pdf manual, does not show the ball and cap that is most likely to be in the bowl. nor is it mentioned in the instructions.
I am going thru one just now, a NEW one, and when i opened the bowl. that ball and cap fell out.

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1968 a108 van, "travco family wagon" rare camper conversion