Is there a number one source for new parts for old vehicles?

[MichMan]

2. I would buy a copy of Hemmings Motor News

Huge monthly classifieds all about the old car hobby. Lots of specialty cottage vendors that specialize in old cars.

Looking at one, I dont see any specific IH vendors, but there are many who specialize in various parts like carbs, alternators, starters, gaskets etc.

I agree with Rock Auto, but I have a somewhat unique old car and a lot of parts they say fit most certainly do not, so you need to take their listing with a grain of salt. RA also has no inventory of their own and drop ships everything; you can order three parts that end up coming from three different places, so they charge you shipping for all three separately which can get frustrating