[NorCam]

Get a better picture of the date cast on the rear bell housing flange (passenger side) as that's when the block was made. Sounds like it might be 0 B 3 which is likely 1970 - February - 3rd. Also see if it has a small thread in plug in the front of the block just above the timing cover.

The stamp on the front pad is CE394394 and this is a counter exchange stamping used as a GM warranty block. No one knows why they stamped the codes with the spacing on the last 2 characters but that's the way they were stamped. Blocks were built in large batches for warranty use and that's what the CE designates. The first number after the CE corresponds with the year it was issued under warranty. That being said it appears to be issued as a warranty block in 1973 and could have been for a Vette, P/U Truck, Camaro or just about anything in the 300hp range. Also see what numbers are cast on the main caps since your friend stated it was a 4 bolt main block.

If he can take better pics of the casting numbers, front of the block and the bottom caps he can email them to me at oldgasoline101 at gmail.com. If it's an NOS Flint block with standard bore in good condition (meaning no rust or pitting in the bores and build-able as is) then it's likely worth a grand or so to someone looking for a warranty coded block from that period.

Cheers