Hi folks, I'm currently rebuilding my OBD1 engine from the bottom up. After doing a lot of research it seemed that it is possible to use an OBD2 head on the earlier block and since I had a brand new one I thought I'd use it. I noticed that the oilway on the chain end is very different but again after a bit of searching on here and vortex it looked as though this wasn't a problem. So, in went the head bolts and I torqued them up. It was only after standing back to admire my handywork that I noticed a round port on the inlet side that didn't exist on my original head? Can anyone tell me what it