I’m having my 500 efi’s rebuilt and the thermostat housings are not usable. Seems as though Mercury has discontinued that particular part. Has anyone got an alternative for this part? I have heard maybe the GLM big block housing may work. Can anyone confirm this? If so is there modifications that would need to be made? I’m sure I’m not the only one out there that has experienced this problem. Thanks in advance.

Someone posted the other day Sierra versions on amazon.

not sure what they are like

These???? Mercruiser thermostat housing with brass tee

That's the ones. These pop up on another site after we machined the GLM to work. Thanks for posting though. I'm sure someone would like to get their hands on them.

I did the same on my rebuilds

Winter repower 500 EFI's