That's because 99% of the stores are crap, their stock is crap and the management is crap. They can't keep people long enough for them to learn what's available to them and the customer. Frankly most of these people have probably never worked on a car it seems. Let alone a car or truck made before 1990.
I know your frustrations, I love to wrench on my stuff, cars, trucks and especially motorcycles (much easier to work on!), however there is a serious lack in local stores being able to provide knowledge on parts and decent quality parts. I gave up on those places. I spend a little more for parts from the dealer or guys like Mark, CCOT, MAF and yes the almightly shipping monster SOR. I may pay more for the parts but I always get what I want, it almost always fits properly, works properly, (unlike the countless new parts I've bought that were junk right off the store floor) MOST importantly I get to talk to someone who knows what I'm looking for. That's golden man.
My time is valuable once it's gone it's gone, that's worth the extra money, NOT wasting my time. I'd rather be enjoying myself not banging my head against a wall, let me tell you, my 40 has tested those limits to the fullest. I almost bought a 40' ford pickup the other day and would have gotten rid of that thing. thankfully, I woke up from my stupar. Hey good luck sorry for the speech but I hope others can learn from our struggles.