Oil Level Question

[Old Crow]

So, we're getting ready to start this truck('54 3100). Stock 235 more or less.
My son puts 5 quarts of oil in the engine...gives it a while to drain, and it doesn't show on the stick. Adds another, still doesn't show, adds another, and it just barely shows on the tip of the stick. I mean like maybe a 1/16" on the tip.
Took a piece of 3/16" brake line and stuck down the tube until it hit the bottom of the pan, and there's plenty of oil(as you can imagine). So, since the dipstick appears un-altered, the only thing I can think of is the tube is too long.
I pulled on the tube, and it came right out of the block, was only in about 1/2". So, now my question is, "Was the tube all the way into the block?".

Can anyone tell me how far above the surface of the block the top of the dipstick tube is supposed to be? Or, alternately, the distance from the pan to the top of the tube measured with something besides the dipstick. I'm thinking that the tube isn't down in the block far enough, but before I just drive it down in there, I wanted to consult the collective.