This a freshly machined chevy 350 block.It is a four bolt main block.It has been machined .30 over, hot tanked , magnafluxed , and has had new cam bearings and freeze plugs installed.The block # is 3970010 which means it is a 1968 - 1975 block it also has a 10 and 20 on the front of the blo0ck which means it was made with 1% more tin and 2% more nickel making for a harder block.Thank you for looking. Location: Millersville Maryland it's NOT ok to contact this poster with services or other commercial interests maryland