The INdy is not date stamped but they do have serial numbers that you can call Indy to get more info. Or just send me an email and I will get you a copy of the original order. On the indy blocks, take a boroscope or bright light and go up the main oil feed holes to where it intersects the main galley. Make sure that intersection is fully drilled and free of slag and crud. I also enlarge the oil drain holes on the top of the cam tunnel about double what they come at. I also drill a small hole in the China wall in the front of the block to allow oil to go down the front of the block. Other wise all it gets is splashed off the crank up there. Important for gear drives and timing chains both. Wash, wash and wash it again......Todd