determing engine block numbers

[doubleb's69]

Originally Posted by 72 K20

SSTim
Thank You for the results ! I'm pretty positive on the S in the TDS code and Bruceman1968 could be right,, the engine has a sticker on the valve cover from a local shop that has long been out of business suggesting that it is not original to the truck.

The K1212CDD is probably a 305,, it has an aluminum Q-jet intake and this seems right for one of the so called "high output 305 ". I will have to tear it down to see what it is. I know that the cam is flat on several lobes so it is ready for a rebuild whatever it is.

The TO527CLB is in my 72 C20,,the truck came with a 402 but I didn't think it was original to this truck. Either way,, it's a big block and will be coming out.

The K1212 CDD was pulled out of an 88 van and has TBI on it with the pan mounted dipstick.
This is the motor I wanted to build for the C20. I sure think that GM could have come up with a better code system.

Prime example The LS3,, 71 or 72 402,,,,, or the LS3 vortech. How about the LT-1 ?

If it warms up some I will try to get some casting numbers off of these small blocks to zero in on the year,, that will probably tell us what they are.

I thank you all for the information and discussion !! I will be looking forward to future postings in this thread !!!

Take care everyone !!!
Tom

LT1 would be CRT, CTB, CTR, CTU, or CTC. Right now there is one on Des Moines Craigslist dressed up like an LT1 short block for $250. There is also a guy in Altoona selling a LT1 780CFM Holley and a set of LT1 rods and pistons. I hate being broke. The 1970 LT1 is my favorite engine.
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