On 1982 or so and up 5.0 blocks, the dipstick goes into a hole in the drivers side of the block.
On a 1979, it goes into a similar hole in drivers side of the oil pan, where there is a cast boss riveted to the inside of the pan.
On earlier ones, 60's to early 70 it goes into the pass side front of the timing cover. I think all of the covers have the boss cast in still.
Yep, I installed a later oil pan with no boss onto my 79 block with no hole. Had to change it out to install the dipstick.