Will appreciate if someone can tell me different options on where to purchase 1" over stock rear coil springs for a 1966 chevelle.

Got mine from Eaton Detroit spring Co.

Detroit Eaton is a great choice however they tend to get a little pricey, but they do offer GREAT products.

Another option is to go down to your local "GOOD" auto parts store and ask them to allow you to look in their Moog Coil Spring catalog (if they don't have one you are in the wrong autoparts store).

In the catalog, find the stock rear coil spings for your Chevelle and then using the tables and listings in the catalog, determine their specifications and find another spring (with the same style ends) that has specifications a little closer to what you are looking for. Also keep in mind that if your Chevelle still has original springs or even 20 yr old springs for that matter, they are probably sagging quite a bit and new springs, even stock original right height springs will probably raise the rear a bit. I guess what I'm saying is, would you like the rear to sit 1" higher than it currently does with the old springs or would you like it to sit 1" higher than it did on the dealer's lot in 1966?