unknown year 350 what do these casting #'s mean

[scoopy03]

on the ledge where the left head when looking at the engine from the front is the casting of 14y149395 and k06-17cmp and on the top of the block by the transmission is 3970010. what numbers tell what year the block is. i was told it was a 74 chevelle block but most of the parts have been changed so these are the only accessible castings i see.

[maxwedge]

Mortec.com has casting # info.

[silicon212]

Originally Posted by maxwedge

Mortec.com has casting # info.

I'll second that one. Mortec has perhaps the best resource online when it comes to Chevrolet casting numbers.

[scoopy03]

already tried there and looked again to make sure i didnt miss something and nothing it close to the other castings i found

[silicon212]

Originally Posted by scoopy03

already tried there and looked again to make sure i didnt miss something and nothing it close to the other castings i found

The first two numbers are the VIN and serial number of the engine assembly as it left the factory. That's not going to get you far with what you're looking for.

The number ending in 010 is a 350 block, two-piece rear seal with driver side oil dipstick. It could have been made anywhere between 1967 and 1979.

There are other numbers on the back of the block near the bellhousing mount. That will tell you year and date made.

[hotrod_chevyz]

Its hard to tell what year it was made since they used that casting for many years and for many different configurations. If its "hencho de mexico" it may be prone to cracks ect making it a boat anchor.

On the other hand some blocks sharing this casting number were used for high performance applications. Certain numbers on the caps can signify that the block may have high performance roots. You can also look for a number to see if its one of the high nickel blocks, wich are the ones worth having. I dont remember what the numbers are right off hand if i can get by the shop some time soon i will look it up.

The numbers in front of the cyl head give clue to the block configuration, meaning power output most importantly. Once the pistons and heads have been changed they are pointless. The two configurations on my own block were T1027CLJ or T1027CKJ. The difference between the two is like 50 HP. One had a slightly more agressive cam, and flat pistons as opposed to the lower compression dish pistons.

[Blue Bowtie]

Look at the front bulkhead area (where the timing chain lives) for a "010" and/or "020" cast into the wall.



That example shows an "020" at the right (left, as viewed from the front) of the main saddle. Those numbers will reveal if any additional tin or nickel was alloyed into the iron for the case casting. More nickel makes for a lot more resilient casting. That example has 2% nickel added for more casting strength.

You might also want to look closely at the starter mounting pad. If you notice any core shift revealed by the starter mount hole machining, that can also indicate thin casting sections in the lifter valley corners. If it isn't going to be a high HP build, it probably won't matter much. The photo shows what might be a "problem" case casting. At a minimum, that casting would need some welding and machining to rebuild the starter mounting pad. These are the SBC engines which seem to always have a noisy starter, regardless of what kind of shims are added.

[hotrod_chevyz]

Most of the 3970010 blocks ive seen were 4BM blocks from 70's Chevy trucks. Small valve heads, punk cams, and dish pistons. All they need is 040 bore with flat forged pistons, big valve heads and a non punk-ass cam and they can make some good power, even by todays standards.