As far as a LIST of what years used what casting numbers ?????

GM probably had documentation of such stuff, but I have never seen any definative listings.

There were definately overlaps in production runs of engines.

Depending on the total production of trucks and the production number of engines, the overlaps could vary.

The "660" 6.2 block was common for several years.

The last 6.2 engines were built on the 599 Block and were identical to the 6.5 except for the bore size.

The one piece rear main seal, crank and pretty much everything else was the same as the production 6.5

This change occured in the 91 model year in preparation for the introduction of the 6.5 in 92.

There were a lot of changes over the years that were phased into production.

One case in point was the mods to the oil pans. The GMT400 trucks (4x4) had to have a notched pan to allow fitting around the IFS gear box up front.

These same pans were used on engines that were installed in the V series trucks such as the Burbs, Blazers and the crew cabs of the "OLD SQUARE BODY" design.

Trying to figure out all the little nuances of numbers and such will drive you to drink.

Also after soo many years, the stuff has been swapped all over the place and into who knows what all sort of places that it never came originally.

The glued in tag may or may not have any real meaning.

I have seen a buttload of MIL engines and have not seen any tags on them.

I dont have any knowledge as to any practices of the MIL tagging rebuilts.

The stuff thats repaired in the field (combat theater) are usually running repairs.
If an engine has serious issues, they are swapped out with a fresh unit.
As far as I know the field shops do not do major repairs.

Robyn