Technical what is it?

so, i'm working on a 1951 chevy styleline deluxe and i discovered this thumb wheel that is on the side/back towards the fire wall of the distributor. can anyone tell me what it is and its function?

 

sorry, i forgot to post the pic!

 

Octane selector.

it’s to make minor adjustments to the timing.
As fuel back then was not as good as it today and octane ratings where all over the place.

buy a shop Manuel there cheap and best investment you’ll make.

 

I think that is a very early distributor with a grease cup. Remove. Fill with grease and replace. Every chassis grease job. Turn it in a little.

 

My 53 has one too, grease cup.

 

Grease cup.

The octane selector is part of the vacuum advance unit, that mounts the distributor to the block.

 

You guys are right, I’m wrong

 

Man I feel better now,,,,,,I knew what it was,,,,I thought he was just messing with him .
I guess it was an honest mistake .

Tommy

 

YES!

Ben

 

thanks ya'll