Classic Industries Or National Parts Depot, I got full quarters for my 69 for NPD and the steel was heavier than the quarters i saw from other outlets, they are all over the place you can buy just about any reproduction sheet metal for the 68's. on the other hand finding 69 convertible sheet metal is harder. Classic Industries full quarters are on page 373 of the latest firebird catalog.
Zak 1969 Firebird Convertible 400 1982 Trans Am 1964 Understanding Long Term Domestic Partner 2 Cats