Bit more digging thanks to Charles. Pump ID shows 17 not 117, no R on stamp. Pix show base where it appears a ring was added top and bottom to expand to 10 gallon. Latest patent date is sept 1923. So is this rush? Inner face of cylinder groove is 13", outer is about 13 5/8. It is 22" tall, ten 3/8" rods. Thanks guys, a lot to learn. Btw it has 0 gallon tag at top.

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If it's automotive---