camaro block for 69 to 70 also used in some trucks and cars. Good chance its a four bolt main block. I have one in my garage right now that is four bolt from a camaro.
I also think this a good block as far as rebuilding goes i would use it for sure. I find a lot of the 010 blocks are four bolt mains but its all a crap shoot until you pull the pan and check the mains and crank numbers. then you can tell for sure what it came from.