I listed these on eBay and expected them to sell pretty good.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=014&sspagename=STRK%3AMEUS%3AIT&viewitem=&item=330100448361&rd=1,1

Got a few emails after the auction, but I've decided to just put them up in the attic.

Was i wrong to think a NOS set of AC brackets was worth more than $50 ?

Maybe :) Sometimes it is a timing thing, the right person didn't see your auction. Also NOS is overused on Ebay so there is a good chance folks do not believe they were NOS. If you don't have factory packaging folks will not believe you.
Does anyone like Ground Up sell the the brackets? That could be a big detractor if they are available new. I found a set on www.firstgen.com for 67-68 camaros with hardware that might be close and they are $125 and you have a couple more pieces. You could always try a relist.

Another suggestion is to list them year specific as apposed to 283/327 AC Brackets.

Alot of people search year specific to their cars.

It read to me like you didn't believe in your own part. If you don't even believe they are NOS and never used (ie "looks NOS to me", "Finish looks like factory") then I certainly don't. The ad reads to me like you don't think they are NOS but that they are repainted. I also agree with above, a year in the title would help. If you search "chevelle" on ebay its unmanageable you have to use the year of your car. A year specific search would drop your ad out of the listings returned, and thats bad for you.

I agree with the previous responses. Also, you write, "I don't remember the specifics". Find out if the parts are original or NOS and be specific.
Also, take some quality up-close pics of any part #s or GM stampings.

All the con artists are vague in their descriptions. As soon as people get that feeling, I think that your auction is doomed. People are getting leary of buying from e-bay anyway so it doesn't take much to turn them off. If I buy parts for our '69, I want '69 parts to arrive. At a swap meet you can check the parts out first hand. Not so easy on e-bay.

Here's a title I would use:
NEW 283 327 Chev AC A/C Compressor Brackets 1964 1965

It's 53 characters if I counted right, and should hit the most searches. In your text, I would describe them as:

These are a full set of new A/C compressor brackets I bought for my 1965 Chevelle Wagon. I bought them from (dealer, repop?) back in (about year), but never got to using them. I'm (back to working on the car/clearing out spare parts), and never used them because I went with the new Vortec heads which means these won't work. They still appear new, and don't ahve any bolt marks, the finish still has the factory dipped look too.

I would also go get a USPS flat-rate box (free from post office) and ship them for $8.95 (cost you $8.60 with tracking). Hit the free re-list button, and then make some changes. I would think $50 isn't too out of hand, but you may want to start them under $40 hoping to get more people to bite.

I agree with all of the above ............. don't assume in your ad, just tell what you know for sure. $50 is a fair price to start with, anyone in need for these parts would gladly pay that and more......... but again it's a matter of timing. I've been looking for a original 4-speed boot & bezel for months.

SBC short water pump stuff is pretty much worthless. It's not you, there is no market for it. BTW it's 64-68 is what it fits
Edit, please allow me to clarify before someone misunderstands and flames me. I was really shocked when I first started looking for BBC swp A/C components to find the SBC stuff didnt sell, and when it did was for peanuts. I would think someone would want a highly desirable set of NOS brackets, but the market is buyer oriented for those parts. With the cost of the stuff, sometimes I wish I had a SB ( sometimes) lol. Good luck. JN