back in the early fiftys my dad had a 39 merc 4 dr sedan and the fuel pump died ,he removed the odd looking pump and when he when to the local parts house the guy said it was from a canadian bus,that may explain why the car was very peppy..
I have one with "59Y" on the bellhousing but the "Y" is upside down with respect to the "59". Is that the way yours is? It also has the factory reliefs.