let's say that you have a new 71 Challenger six pack and after 9 months you break the engine. You go to your local Mopar dealer, and the engine is deemed unfixable. So a new Service engine is ordered. How are the markings on this new service engine? If it is still a 71 casting, doeas it have the G440 markings on the upper pad? Is it marked HP? The vin pad is blank...but there should be an assembly date on the lower part of the engine. My 426 Hemi is marked february 2 70, with the car being built january 15. If the engine would break in say 73, would the engine be a 73 model, or the service department tried to install another engine with similar horsepower and build date?
Thank you

I have a end of Apr 71 RR and the 383 blew, so they had run out of 383s and installed a 400 short block.

Can't fully answer your question, but I have a 1973 340 with a 2/9/73 casting date. Neither the VIN pad nor the left front of the engine have ever been stamped. It does have a cast crank, BUT is most definitely internally balanced. All of that adds to my guess that it was a replacement engine for an early 340. That engine was put in my GTS some time around 1980 by a private party (not the owner at the time). Exactly where the motor was before that is anybody's guess.

all the ones that I have seen had a metal tag riveted to the side of the block with replacement part number, date would depend one how long Chrysler had it in stock could be a year or two old