Hi guys. New here, but have had this engine for probably 15 years. It is a 3970010 with the 10 dot clock right next to it on the rear flange, so I am guessing is a Saginaw cast block. The only issue is that I can't find any ID numbers on it except that. The pad in the front on the passenger side is a lot smaller than any other engines I have seen and even though the numbers could have been machined off at some point, it doesn't seem to even be large enough. Any ideas where any other number may be? I have checked on the area behind the oil filter on the outer edge. I attached a picture of the pad in front of the passenger head just so you can see what I am talking about. Thanks.