Hey guys. I recently bought a 99 dodge ram 5.9 magnum. The dash says 230xxx. The guy i bought it from claims it was swapped with an engine with 20xxx miles on it. I already know that part is untrue, however the thing does not drive like a 230xxx engine. Ive searched everywhere and even emailed mopar about where the serial number is, i cant find it anywhere. However i did find the casting number. Every casting number on google is 53020006-360. However mine is 53020006AB-360. WHAT DOES THE AB MEAN!? Also if anyone does know where the actual serial is, id love to know. Thanks!

The letters at the end of the part number are just the revision of the part. Their *should* be a date stamp on that same side of the block somewhere, though it is likely not in an easily recognized format. You won't find a serial number on it.

I believe the engine in your 99 is the 4 wheel drive version put into last 2002-03 models 1500 and 2500. It was just a heavy duty version of the 360 with an additional mounting holes on the block and a change in roller rocker lifters.