Is it a mercury or not ? what is it ?

[charlie fitton]

for one of my carrier engines stamped into the machined area on top of the block where the intake manifold sits.

If you have a true "carrier" engine the valve seats are hardened inserts - they were apparently planning on using a lot of alcohol if they had to.

I think your best bet for parts is MACs in Queenston NY. even the big "doublewide" big end bearings. On-line catalog and the Yankee Dollar is down a bit...