Finally got the dipstick figured out. Couldn't tell online whether what I purchased was right, then I received it. Not even close. I think all the other dipsticks are for cars, where the length isn't a big deal. If you haven't considered it, and you have a "short" dipstick now, pop your hood and stand at the front of the core support. Now imagine that the dipstick is at the front corner of the passenger valve cover. FWIW the "ZZ4" (I assume it's just a standard car piece, but is often listed/sold as ZZ4) dipstick ends up in about the same spot as the one in the truck now, except opposite side of the engine.
Did find out that sometime between 1990 and 1997 GM changed the dipstick and tube, at least on the trucks. Both truck dipstick/tube styles are similar, however the "early" style does not use an o-ring to seal the dipstick to the tube. The early/late tubes are not interchangeable, nor are the dipsticks. Additionally it looks like the '97 had a spark plug wire holder integral, probably plastic, all that is left on this one is a serrated piece sticking off the mounting tab.
The truck dipstick I ended up with came off a core engine on the ground, so unsure of year. But same as on a '97 that was still complete.
Oddly (to me), the ZZ4 dipstick tube protrudes into the pan a bit less than the truck one:
You can see the mounting location and that the ZZ4 dipstick goes forward just past the second from rear valve cover bolt. Trivia: the bolt threads for the dipstick in the picture is 1/4", the one 2" forward is 3/8" or similar.
Truck dipstick goes straight up a bit more before angling sharply forward:
...and comes out past the valve cover. And mounts in a different spot (also 1/4" however). This is before I painted it. The dipstick tube must get hot on the trucks for some reason, it had burned off the paint in the bright area, and the dipstick itself is pitted/discolored slightly from heat as well. We'll see how well this clears the header.
Finally, here you see that all said and done, where the dipstick measures the oil, is the same. Which should be obvious if you think about it.
Hopefully purchase a new clutch tonight, and some walnut media to blast the paint off the new flywheel surface. Last component I can think of needing, then I have everything needed to start tearing the old engine out of the truck.
