Hi my dad and i just bought a 64 impala with a suposed rebuilt small block chevy. Its definatley a small block and there is a tag on the left side of the block in front of the motor mount about the size of a credit card that says remanufactured and has the numbers 966664 on it. I haveanother GM motor that is a 350 goodwrench rebuilt motor that is bored .040 over and has a restamped block number but not a tag like the 1 in the impala. Has anyone come across this or know how i can track the numbers to know who rebuilt it. any advice? thanks