The story of the first 4 NASCAR kits is interesting. The kits had flaws. Most of this was due to a time frame set by GM and Ford. The GM kits were pretty good but the cross over headers were hated by most teams and few used them. But they were on the car GM provided Monogram. (headers from 1/24 Monogram Tri Five Chevys work well for more correct)

The Thunderbird had more issues. The model we got was a mock up of what Ford had Banjo Matthews build for NASCAR to approve (and use in film Strocker Ace later) The prototype had lots of issues NASCAR and teams wanted fixed. But Ford was helping fund the kit (they had done that on a few models) but it had to be on the shelf by 83 Daytona 500. So kit was rushed to production with the info they had.

All this comes from designer Bob Johnson when I worked for him at Accurate Miniatures in Charlotte NC. Thanks

My version with small fixes. My biggest issue is headlight doors being flat and not stepped. A hard fix