Just my 2 cents: I don't think I'd add a quart. You don't want any chance of the crank sloshing in oil.
With the dipstick I think I'd mark it, pull it and cut it with a pipe cutter. Clean cut, no shavings to worry about and probably easier than trying to cut it installed.

 

That sounds like a plan there.

 

It is pretty easy to remove a dipstick tube. Remove it, cut, clean, and reinstall.

You can probably add another 2-3 quarts over spec and be fine.

In the 6 quart system, there will be about 5 quarts in the pan and 1 quart elsewhere in the engine.

With 5 quarts in the pan, the oil level will be just below the bottom of the oil pickup tube hole, which is about 2" below the pan rail. Because of the angle that the engine is installed, the oil only covers about the rear 2/3 of the floor of the pan. A 292 rotating assembly passes only about 1" beyond the pan rail at the most.

Another thing to throw in the mix, there is a larger capacity truck pan, 7 quart system. I think it was for heavy duty applications. If you have that pan installed and add only 6 quarts, then it will indicate low.

6 quarts should pose no threat because that is what is called for. I've run 7 quarts with a 6 quart system pan to try to address an oiling issue while racing. Didn't fix my problem but didn't cause any either.

 

Ok, that's what I figured, wanted to be sure. I'll just get me a cheap pipecutter and get this stick to read correct.