New sheet metal going on, new quarter panels and Rear Body panel.
Rear Body panel
All Years Pontiac Firebird Parts | 15010 | 1974-78 Pontiac Firebird; Rear Body Panel; EDP Coated | Classic Industries
https://www.classicindustries.com/product/15010.html
Rear cross rail
https://www.classicindustries.com/product/all-years/pontiac/firebird/parts/152791.html
Quarter panel to Rear Body panel filler
https://www.classicindustries.com/product/all-years/pontiac/firebird/parts/153563.html