This is for 5 Jahns Racing Pistons.  Jahns stamped on the inside of each.  080 stamped on the top.

I acquired these with a collection of Hudson parts from a friend.  They've been on a shelf in my garage for the past 10 years as I don't know there application I've been hesitant to do anything with them.  Prior to me getting them, they were in his workshop.  Now he repaired saw blades and his workshop was covered in black dust.  These were stored in the box with the flat side down so they collected a fair share of dust over the years.

I took pictures with measurements hoping they'd help someone better ID them.

I ship weekdays with ups ground and usps ground advantage.