timing chain install question

I just replaced the timing chain on my 273, mileage unknown but the chain had about 1" of play in it. I've never done this before, and I had a friend who has, helping. Once we got the timing cover off, we noticed the dots didn't line up at all, but after we rotated things they lined up. I put the new sprockets on but found the dots didn't line up quite right, they were off by about 1/2 a tooth. If I moved them one tooth, then they were WAY off, so I put them as best as possible and chalked it down as "as good as it gets". My woodruff keys appeared to be stock. I believe offset keys are used when you get into setting your timing with a dial indicator and all that...too fancy for me!

Anyhow, my engine runs like crap, but it did before too...so I think there's some other problems. Overall I enjoyed the experience and I'll likely do it again sometime, I'm much more confident now.