What a bummer, sounds like we have to modify kits that were intended for these trucks in particular. I am local to CPI in Houston, I wonder if I took them a truck if they would be willing to modify and correct the brackets for these trucks to offer in the future. It's a good thing that we are coming up on the cooler time of the year so I have time to get this all worked out by late spring.You should read posts 301 through 315 in my rebuild thread. There are issues with the compressor mounting brackets furnished with the Nostalgic kit. These issues can be corrected but not easily. Nostalgic does not produce the mounting brackets, but instead purchases them from Component Parts Inc. in Houston, a small mom & pop machine shop which does not have a website and does not accept credit cards. Nostalgic then re-sells the brackets along with their AC kit.
There are differences between the Nostalgic and Vintage AC kits. As previously stated, the Nostalgic kit includes the compressor brackets, however the Vintage kit does not. The Nostalgic kit provides AC only and leaves the 35-year-old heater core in place. In contrast, the Vintage kit completely replaces the entire heater box and core, and blends dry conditioned air to the new defrost plenums. This blending of dry conditioned air will clear a fogged windshield much faster and more efficiently than the OEM heater-only defrost mode. Also, the Nostalgic kit utilizes the OEM cable-operatied control panel, where the Vintage kit completely replaces the factory panel and cables with a new electronic panel.
For my P400/700R4 build, I purchased the compressor brackets directly from CPI in Houston, and purchased the Sanden compressor from Summit racing. When the time comes, I will also purchase the condenser from Summit, and then purchase the behind-the-dash evaporator unit from Vintage.
Hope this helps.