I'm new here to the message boards but have gotten alot of good information from it so far and figured I'd pose a question of my own.
I'm currently fixing up an 88' Z28 and come to realize my door hinges have gotten worn down, alot.
So I wanted to know if I had to buy the specific Upper and Lower hinges or if I could just buy two lower hinges but use them for upper and lower (for money saving purposes)
Note- I would just replace the pins but the former owner jerry-rigged the upper hinge so that it wouldn't need a pin

 

The door part of the hinges is welded to the door afaik - not an easy job to replace.. The easiest way to fix them is the kit from TDS. I bought the kit and am working on restoring my doors.. Hardest part by far so far is getting the detent roller pin out from the lower body side hinge.

 

First of all, keep in mind this involves taking off the front clip, fenders, and hood, to even get to the hinges (unless you have some crazy wrenches). Not a big deal if it's a project, though...

First, check out the bottom hinge. Pay special attention the bushing holes in the door side half (make sure that a replacement 'oversize' bushing fits in tight enough), as it's welded to the door and can't be replaced. Also, be sure to check the condition of the area around the hinge on the door, as normal leaking causes this area to rust quickly. Either one basically involves replacing the door, as a $100 door from a junkyard is a lot easier than the extensive welding you'd need to replace the hinge.

As long as the top hinge is fine (tight enough), then don't worry about it. If needed, you can drill out the 'rivet' pins and replace them with standard oversize bushings and pins. Little loose, but works if necessary.

So basically, the only 'replaceable' hinge is the body-side half of the lower hinge...