Deciphering Engine code stamps

I am new to the site so please forgive me if this is posted elsewhere.

I purchased a Chevy 350 but in the process to decipher year built and partial VIN on the engine If I could get help deciphering the codes to what it was out of. My first attempt to decipher told me it was a 1968 327 based on beginners research but i believe i am wrong with finding the rest of the numbers stamped on the block and now think it might be a 305

Engine casting number : 3970010
Date stamp: K 10
Engine Code: K 01 21CMR
Partial VIN Stamp: 141435 62

The engine does have a Carter AFB 4 bbl carburator, 2 bolt main. There are no stamps around the oil filter.

By the information what I have found Casting number it can no longer be a 327 given the date stamp and partial VIN but that is where I am at a loss. Date stamp says built in 1970 and the partial VIN says it was built in 1974.

It’s a 220 horsepower 350 originally installed in a Corvette or Camaro (Z-28) with a manual transmission. It was manufactured at the St. Catherines plant (Ontario, Canada) on January 21, 1978.

Thanks that helps a lot.