what app uses a 5/16 (.312") 2.02 intake valve

I need a valve to make a piston notch cutter & I have called the auto parts stores & they have checked some but they pretty much say they need a make/model/year/eng to help me find one. Thank you for your time.

You might look through SI valve's catalog.

http://sivalves.com/catalog.html

I'm on it, thank you.