Marvel Greatest Comics 30 color proof

Sal Buscema taking his turn on the Fantastic Four 37 cover. Progressive cover color proofs. Regarding the time period very early Sal cover and one of the few artists to tackle the Fantastic Four following the departure of the King Jack Kirby. Also the first artist not named Kirby to do a FF new cover for this reprint series. Which I believe only a total of 12 new covers were produced for this reprint series as Marvel continued to use the Jack Kirby original covers.