Changing head gasket and timing question

[c150L]

Someone recently said they only saw 2 Zetec 2/0s with blown head gaskets. Now make that 3. I don't think this 96 contour had a blown head gasket when I got it. Drove it 2 weeks, NP. ( did change the water pump though. Last week end, wife drover it and got it hot. )Over heated!) Now, the oil is milky, steam and water coming out tail pipe and lots of bubbles in res.

So, any suggestions on changing the head gasket would be appreciated. I started this afternoon.

When I got the valve cover off, I did my investigation to see how to line up the timing chain. I belive I get it, but one ?? When on TDC, the exhaust cam lines up perfect on the back alignment notch. The intake cam is one tooth advanced. When I did the water pump, I just put the belt back where it was. It still is there. What might be the effects of having the intake cam one tooth advanced? Sometimes it started hard. Last tank I only got 23mpg. (First and only tank checked.) I see a sensor on back of the intake cam. Must signal #1 on TDC. Does that mean all cyl would fire early? Could I have been exhausting into the intake from opening those valves early? (New style EGR?)

Again, interested in tips on head gasket change. Also interested in the 1 tooth early cam setting.

Thanks in advance,
Dale