70’ 340 casting mark or not ?

[schluney]

Quick question - trying to identify the significance of a mark across couple of cylinders (the large X) . I searched everything I can think of and while I found few other with similar mark, I haven’t found an explanations. Block mag’d and sonic tested with good results so just curious at this point.

Block was cast in Aug 70’ for 71’ model year.

 

[str12-340]

subscribed

 

[Dmopower]

Following.

 

[dano]

Marine block? Those bosses on the side don't look familiar either.

 

[schluney]

More detail…

 

[RustyRatRod]

More detail…

View attachment 1716065322

I know that the Maltese cross signifies undersized crankshaft bearings from the factory.

 

[sabre67]

 

[Oldmanmopar]

Looks like someone marked a mold they wanted to keep track of. I don't see any bosses that are unfamiliar except for the shiny indent cavity line above the oil pan rail which could be something in the iron when poured or just a picture shine.

 

[MoparMike1974]

I have half a dozen 340's and never seen anything like that. On any LA for that matter.
It sure looks like it was cast in there.

 

[Garrett Ellison]

Looks like someone marked a mold they wanted to keep track of.

That's my guess too. I'm thinking that were it's a -8 block that the 8th repair at that part of the mold for the sand cores was sketchy at best. I'm thinking they probably marked that particular part of the mold to see that it wasn't going to be used in the -9 series during its next repair.

 

[schluney]

Thanks guys, very insightful and line in the sand theory seems to make a lot of sense.

 

[pishta]

IIRC the maltese cross denotes an undersized main bearing journal (or other non standard issue, lifters?), ie -.001.