440

[440 4 speed]

possibly "R" means undersize rod bearings?

Not that I have ever seen .

 

[Cranky]

Like already said, check it all over. Markings can be deceiving especially from someone wanting to play games. I used to work in a steel mill roll shop for a short time where the rolls for rolling steel were reconditioned/machined and one of my jobs was to stamp the rolls so the name ARMCO would show in the new steel. Well, somewhere there's steel that was rolled with the name OCMRA instead. Anywhere there are humans involved there's going to be errors or just plain goofiness.....

 

[allmoparparts67]

Thanks for all the info. I googled it but find the right answer.

 

[66Satellite47]

A word of caution, any block stampings on a block that is not truly "virgin" can have stampings that could mean anything. I've had numerous blocks that had various "aftermarket" stampings that don't correspond to the factory markings. The factory service manual usually has the description of the stampings.