Town I grew up in, Freeport, Long Island, had a place many years ago called Collins Auto Parts. They had a machine shop on premises and had just about every part known to man in stock. Once I was established as a reputable mechanic, they used to let me search the attic and watch my stuff get machined. Long gone now.
In Merrick, the next town East, there's still Colvin Motor parts. They have a machine shop as well and you can get ANY part there. Even though I live twenty miles away, I still go there when the need arises.
Closer to home in Bayshore is a store called Mars Auto Parts. Last of the old school stores. I like that place too.
In (I think) Farmingdale, there's a shop called S-K Speed. Haven't been in there in a few years because the last time I was in there they had more tuner stuff than I cared to be around. Last of the old school, over the counter speed shops though.