This is how I did mine . The car I started with some 30 years ago should have been crushed but I took pitty on it and saved it .Used it for the past 30 years and now it's time to do it again and I'm going to do it the same way. I used 2 door quarters because I could get them. I think they were 65 Barracuda .You need to use the very back of the original wagon quarter but everything in front of that will work from either a 2 door or a 4 door. Anything can be fixed if you want to take the time and put in the effort . My 65 wagon started out as a total rust bucket with a 225 and an automatic and ended up as a good work vehicle with a 170 , a 4 speed , and a 7 1/4 sure grip 323 rear . See photos. The last 2 photos are what she looks like now as she awaits the second resurrection .