Looking for motors for a kid I sponsor in IMCA Hobby Stock. Found a motor on FB marketplace and theres a number on the front of the block I havent seen before. Was wondering if anyone could help tell me what it means. The block is a 3970010 sbc, but on the front of the block next the timing chain cover is the number 509. Need to make sure this block is ok for what I need it for. Thanks in advance!!!!