Engine block code(s) correct for 72 and others

[DeadheadNM]

What are correct block codes for a 350 in 1972? My Blazer motor has two terminal letters I suspect are "C" and "E" - the motor was probably decked so these are subtle but I suspect the motor is original. Codes are located on a boss on the RH front of the block visible from the pass fender side. I have codes for K10s and K20s (they start w "T") but no K5s. For those who have original 350 4v motors in their Blazers, what are the engine codes? Mine has CA emissions equipment if that matters...thanks Pete

[1972Blaze]

I believe CE stands for Counter Exchange. If that is correct it could have been a warranty replacement engine.

[DeadheadNM]

Thanks! Plot thickens - I was wondering if the "T" was be decked off (TCE motor?) - curious to know what should have been in the truck (it has a TH350 tranny). Counter exchange is not something I'm familiar with - maybe that is case. All the little 4wd specific underhood parts are there: correct 4wd dipstick, bracket for AC vac pod, etc.

[1972Blaze]

I just pulled this off of the Corvette Forum. A super knowledgable guy posted it.

"The "CE" block (and "CT" transmission) coding was introduced shortly after the 5/50 Powertrain Warranty went into effect for the '67 model year so the GM bean-counters could track the 5/50 warranty costs vs. the usual number of service replacement engines that were ordered by customers for normal customer-paid "over-the-counter" or "out-of-warranty" engine replacements, when it became obvious that the true cost of the 5/50 powertrain warranty was going to be FAR higher than the predictions when the program was sold to GM management.

"CE"-stamped engines were supplied two ways - as short blocks, or as "fitted blocks" (block and fitted pistons, no crank or rods), the assumption being that all the bolt-on parts would be swapped over from the customer's failed engine. They started out being coded with "CE" followed by a number which indicated the calendar year they were built, and a sequence number which indicated how many replacement engines that particular engine plant had built that year, and shortly thereafter Flint Engine added a second letter digit that indicated the month built - don't know offhand if Tonawanda did this or not. The dealer ordered them from a chart that showed a part number for the engine assembly for each application so the engine would have the right internals, but this part number wasn't anywhere on the engine itself - only on a tag and label on the crate it came in. Occasionally "CE"-stamped short blocks were sold over-the-counter for various reasons in those days, but normally customer-paid service replacement engines had blank pads with nothing on them at all."

[DeadheadNM]

The digit after "CE" is 3 - I suppose this is a '73 replacement block.....what if any impact to collectability/originality is a counter exchange block?

[1972Blaze]

If it were a Corvette it would be huge, not sure about trucks. But I imagine there will come a time when matching numbers become even more desirable with these trucks as well. I wish mine had matching numbers.

[DeadheadNM]

Originally Posted by 1972Blaze

If it were a Corvette it would be huge, not sure about trucks. But I imagine there will come a time when matching numbers become even more desirable with these trucks as well. I wish mine had matching numbers.

Thanks! The Blazer was in such good shape I couldn't pass on it for the block alone. If it's a warranty replacement motor/block from GM I'll take it over a generic replacement. When I get time I'll check the heads to see if these are correct for the K5 as per date codes...