60s trivia question...for those who know all

[In2cruisers]

I know someone knows the answer to this............

I have a leaky BVSV VALVE and figured why replace it with Oem part since its disconnected anyway.... yr. 10/1975

Sooooooooooo......Question time...........what size is it if I were to replace with bolt?

Thank you

 

[FJ40Jim]

3/8 NPT.

Whad'd I win?