Not to long ago I got my rebuilt sbc chevy to fire up and break-in the cam. After I changed the oil, I wanted to take it out on the road but it doesn't idle very well in drive. So I checked the timing with a light and it shows 8 degrees retarded. I think that might explain why it doesn't start up easily and won't hardly idle with the vacuum advance plugged off while checking the timing. So I went to change the timing some and the vacuum advance can. hits the intake manifold. If I move the distr. clockwise it won't idle. Do I have to pull the distr. out and try another position? Does anyone make a vacuum advance can that is smaller? Any thoughts?