My two cents on your numbers are this...

I think the 92 at the end of 0315592 was added. The factory number looks like 03155 F56Z, making it the 2,155th "Z" engine made in Flint in 1956.

I agree with Tim, the MRC number is more than likely a remanufactures serial number and the 92 could be the year it was done.

Mike B smile

Mike Boteler

1956 Chevy 3100 Resto Rod
1952 Willys M38 Army Jeep
1983 Jeep CJ7 Laredo
1984 Jeep CJ7
+++++
Silver Spring, MD