[Phillip marvetz]

Well if you are wanting to run a hydraulic cam in a early 273 you could drill into the oil galley if the block does not already feed the lifters, Mopar sells a jig to do this for the R series blocks. Since you don't have the block in front of you it's hard to say though.
I would have assumed they all come machined to oil the lifters but since I've never taken one apart that's just a assumption,lol. I usually just steal the rockers and pushrod's off of them and send the rest to scrap.