I'm going to post part of the ad in case it gets deleted from Ebay:

Block code is YE, there are 7 heads 1 is cast # is 1 1 production A300, 2 heads have cast 50 with pro. I094 and I114, 2 Heads have cast # 46 pro date B193 and A193.the last 2 heads have cast # 15 with pro, date A118 and A158 which apear to best match the block and are the same color The Casting # 0f the block is 9790071 prodution date is A258 or Jan. 25, 1968 on the front vin# 421359 and YE code the code checks to a "b"body which is a full size pontiac 1968 4 barrel 340 hp, the crank has a large N on it with the casting numbers 9773524.