Anyone seen these marks before

[greatwn73]

  The engine is out of the "new" charger and numbers match but found these letters on the side of the block. It does not appear that the engine had ever been out so assuming its factory. Any ideas to the meaning??

[Plumcrazy]

Those are probably the bore sizes.   Even when the engine has standard bore sizes there is always a few ten thousands variation on the actual size of the bore because of machining tolerances.  They will measure the bores and assign them as an A,B,C or D bore size.

They do the same thing with the pistons.  When they assemble the engine they wil install a B piston into a B bore to get the correct clearances.

If you remove the oil pan you will probably also see those letters stamped on the block on the oil pan rail

[greatwn73]

Thanks I'll pass that on.