L133 - Date code.
Originally Posted by mike623
Hi, I am new to this forum. I am in the middle of making a nice street-able hot-rod out of my 79 formula. I am putting a 78 nose on the front. I currently have the car down to metal and the front clip off. I was going to swap the 400 out and put a cheby motor in it but decided if the 400 was worth rebuilding I would stay Pontiac. I recently rebuilt my 350 rocket in my 72 cutlass. I just enjoy having Oldsmobile's or Pontiac's since everyone I know plays with chebys.
Anyways I pulled some numbers from the engine I wanted to see if you all could help me decode and figure out what exactly i have.
Here are the numbers.
407183 YH - This is from front of block under the head on passenger side.
24X143413 - This is from front of block next to timing cover on passenger side.
L133 - This is located next to distributor.
481888 - This located on rear of block on passenger side by head.
When I bought this car 5 years ago I was told this motor was out of a 78 trans-am. I doubt it though.
Thanks in advance, Mike.
Your block was cast on December 13, 1973. So it was either a very late model year 1973 or an early model year 1974.
481888 - Block casting number
- I didn't find this number, are you sure it's not 481988? If so, that would identify it as a 400.
YH - Engine code
- Not used in model year 1973, but in model year 1974 indicated a 2-bbl 400, therefore your block was originally a 2-bbl 400, model year 1974.
- This is going to be the trailing part of the VIN of the vechicle the engine came out of. On a "numbers matching" car, this number will match the VIN.
I got all the above information from these two web sites (it's always good to check multiple sites, people do make mistakes).