My cousin pulled engine from his 68 300 with 80k miles and we found some strange and disapointing things. He bought this car last year but we have known this car from the 70s and has suposedly never had any engine work. It is a 68 engine but 1 has been apart felpro head gasket & rubber rear main seal. 2 has no serial # (replacement engine). 3 the strange part ,on both sides of block written in white are the letters CCCD. What does this stand for?

68 may or may not have a VIN stamped on it , if it does it will be on the rear of the block , bellhousing flange on the drivers side , Auto trans should be stamped in the same spot. The CCCD is factory markings for which size piston got installed to get factory spec piston to wall clearance.

I don't know why you would be disappointed because it has had some work done unless you were lead to believe it was untouched .

Yes he was told that it had never been worked on. As for being apart I dont know what it would they did, crank & bore all std. That cccd on the side had me really stumped. Another thing I talked him into pulling heads while the engine was out for cleanup and paint and found some scratches in 3 cylinders, pulled those pistons to find broken rings. This car has sat for 10 years at one time and 15 for another with out moving. It has machined pad on right side at pan rail but no numbers. I will check back and bell housing flange.
Thanks for info

Could be worse...if it read CCCP I would be worried about it coming from a foundry in Russia

The #s will be on the top of the bellhousing area on both the engine and trans.

That was a pretty good one. Is this an acronym or something else? Would the numbers be stamped on a pad or just on the casting surface?
Thanks