Sorry, I accidently mis identified the 272-292 caps. Ted's I.D. of EBU is correct.

Paul

That is what I was afraid of.  Appreciate the help.

Warsaw, IN

As Paul mentions, the oil pan usually needs to be pulled for a more accurate identification.  Even pulling the heads and checking for a 3.800” bore isn’t absolute as a 292 block could have potentially been bored out to 3.800" and beyond.  If the bore checks out to be less than 3.800", then it's not a 312.  And to throw another curve out there, I’ve run across a 292 block with EBU caps that had its mains bored out to the 312 size so a 312 crank could be fitted without turning the 312 main journals down to the 292 size.

 

As far as identifying a 312 based on the large ‘dot’ on the rear crankshaft flange, there were quite a few 312 crankshafts that were cast as ‘blank’ or with no dot.  If the crankshaft has the 5/16” raised dot, it’s very likely a 312 but no dot being present could potentially go either way.

Lorena, Texas (South of Waco)

Unfortunately this is an area of annoyance with Y-blks. Usually 312 cranks have the one 5/16" diameter dot on the crank flange, but informed sources say this isn't guaranteed. If not there or not visible, the oil pan has to be pulled & look for the ECZ letters on the Main caps. 272s & 292s are marked ECU. If you are buying an engine or car from an Ad, most of them come with 312s, more than were ever manufactured! Buyer beware!

Paul

This may seem stupid but is there any other way to determine if a ECZ long block is a 292 vs 312 than the crankshaft?  Have seen Mummerts site and wanted to make sure.  Just to confirm the 312 will have the 1 cresent on 1 DOT.  Thanks

Warsaw, IN