Trying to find patch panel for under rear seat of my 79 Grand Prix. Any help would be greatly appreciated. Just purchased car and trying to get road worthy before starting mods.

Yearone does have panels for these cars.  They are out there and becoming more popular as you go.  Sherman parts, NPD may also have them.  If you check with a local supplier they maybe able to get them to you.   RIght now all I can find are full length floors so you would just have to cut out the parts that you need but if your interior is still in place you could find more that you would need.

 

Welcome to the site and good luck with your project.

 

http://www.ss396.com/category/gm-ggrandprixfloor.html