Matching numbers and restoring

[Big D]

I heard today that matching numbers does not just mean that the engine matches the body exactly, but rather refers to the relative production time of the engine matching the body. In my case, my 57 has had an engine swap done recently, and there was a 56 engine put in to replace it. I was told that maybe the engine will still match the body because of relative production times, for example, if my car was made in January, my engine may have originally been made in 56 and placed in the car in 57.

I do not have the car in my posession yet, and I do not have the block number or the vin number yet, but I would like to know if the numbers could be considered matching if the engine was replaced.


Also, I will have a luggage rack, chrome for a mid 70's Vette, if anyone is interested.

 

[JohnZ]

From an NCRS judging perspective, the block casting number and casting date carry 525 of the 613 points allocated to the block; it must be the correct casting (3731548 for a '57, 350 points), and must have been cast within six months of the car's build date (175 points). The other 88 points are allocated to the front pad and pad stamp codes; 50 points for the correct stamped engine build date (within six months prior to the car's build date, and after the casting date) and correct 2-letter stamped engine ID code, and 38 points for the appearance of the pad and presence of factory broach marks. The block casting number is judged first, and if it isn't correct, all 613 points are lost (only 270 points can be lost out of the total 4500 for the whole car and still make Top Flight). On cars built after mid-1960, 25 of the first 50 stamp pad points are allocated to the VIN derivative stamping, which must match the car's VIN.