Done with cleaning and I’m putting these back together now and that require sanding the floor height. There’s a clear difference in these seats, the new one in the kit has a hole in the side of it where the one on the bottom, which was in there, does not.

Which is correct? Is the new one from the kit OK to use?

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Either one...
all the new kits I have used lately come wit the top one that has the hole in it.
I have found that if your kit has a new float then the new (hole one) doesn't need as much adjustment at the ball....but if using the old float you need to adjust more.

Thanks John. You have to sweat the details when rebuilding carbs so I wanted to make sure this wasn’t some odd thing.

I set the float to 10mm exactly.

Thanks for the response and hope this helps others who are rebuilding these themselves.

Thanks!