When I finished up my 261, I didn't have a dip stick either. I went to the wrecking yard and grabbed a couple of dip sticks, but didn't actually like the longer look. I finally took the one out of a 216 I had and used it. I filled the engine with 5 quarts of oil and set the dip stick at the right height to show it full, then made a tube that I tapped into the hole in the block which I made to be the right length. I suppose there are other ways, but that worked for me, especially since I wanted that older "short dip stick tube" look.
As far as the oil gauge line, I hooked the gauge up at the regular spot, but used an "L" fitting to turn it toward the back of the block. The line hugs the block above the pan rail and goes toward the back and actually goes around the corner, almost, and up , etc.
