Many of the vendors sell the same parts.

Many people have had good service/experiences with most of the vendors most of the time. Almost everyone has had a bad experiences with one or more of the vendors. No vendor has proven to be a perfect choice for everyone.

click on Links (in the menu at the top of this page)

Scroll down and click on Parts

Yes, there are a lot of vendors to choose from:

American Classic Truck Parts
Jim Carter
Classic Parts
Chevs of the 40s
LMC
Brothers
etc
etc

By the way, maybe someone who has bought the part you are looking for will report their experience with that part. That is good "insurance/assurance"; however, the quality of a part from vendors' may change over time because suppliers change their manufacturers (and vendors may change whom they buy parts from).