The Stovebolt Site Forums The Parking Lot Big Bolts 54 COE 1st steps

Bob,

F54O might be F54Q, which usually indicates a 1954 261.

The best way to ID an engine is to find/post the following codes:
1. block casting code
2. block date casting code
3. head casting code
4. head date casting code
5. Engine Serial Number (which you posted above)

I'd bet you have a 261 (unless someone other than GM pressed that ESN on the block).