Vacuum advance hits upper radiator hose.

Just for shi*ts and grins I put a vacuum tester on my plain jane 302, 2v to see what it would read..no problems, but wanted to try out my new toy. 

It read in the green about 17-18 in.hg. This was in the low end, as I've heard 20-21 is desirable. I tried to advance the dist clockwise to move the reading more towards 20 and the vacuum advance goes smack against the upper radiator hose. I see where all that is necessary is to pull the dist out and move it a couple teeth while keeping the rotor from moving, the caution is that the oil pump rod may fall out if it's raised too far. The car runs strong, and if it ain't broke I don't want to fix it. Is it worth the risk to try to move the dist?

That's always a gamble that the retaining washer is in place on the pump drive shaft. When you pull the distributor out the rotor will rotate some, due to the angle cut on the gears. After you get the distributor pulled up far enough so the rotor is free you turn the rotor enough so the gear drops down into the camshaft 1 or 2 teeth in the direction you want the correction to be in.

What is the timing now, at idle with the vacuum advance removed and plugged?