Hello. I am rebuilding a 74 455 Olds that resides in my 79 Trans Am, in place of the original 403. I noticed the ID numbers on the pad, and it has two stampings, for some reason. Top stamping is 34M220629. Directly below is 34F158993. I have no idea which car this came from, as the transplant was done back in 83. Any ideas what these number reveal? Thanks in advance.

 

Apparently that engine was pulled from one car to replace an engine in another car. When done by a dealership, the dealership was supposed to stamp "XXXXXXXX" across the original VIN derivative and restamp the block with the VIN derivative of the new car. Apparently they got it half right. Both of those are 1974 VIN derivatives. The "F" would indicate the Flint assembly plant, except that Olds didn't build any cars at Flint in the 1974 model year. I suspect that "F" is really a poorly-stamped "E" for Linden, NJ. In 1974, Linden built full size Oldsmobiles. The "M" in the other VIN derivative is Lansing, so it could have been almost any car Olds made (though the 2xxxxx serial number would tend to indicate an A-body). It isn't clear which VIN derivative is the first one and which is the second. If one of the numbers is more centered and the other is above that one, the centered one is likely the original, but I've seen original VIN derivatives located almost anywhere on the pad.

 

Wow, good info. The double numbers had me confused. Thanks!