Silver Age
During the period fans and historians call the Silver Age of Comic Books, Iron Man premiered in Tales of Suspense #39 (March 1963) as a collaboration among editor and story-plotter Lee, scriptwriter Larry Lieber, story-artist Heck, and Kirby, who provided the cover pencils and designed the first Iron Man armor.[14] Kirby "designed the costume," Heck recalled, "because he was doing the cover. The covers were always done first. But I created the look of the characters, like Tony Stark and his secretary Pepper Potts."[15] Comics historian and former Kirby assistant Mark Evanier, investigating claims of Kirby's involvement in the creation of both Iron Man and Daredevil, interviewed Kirby and Heck on the subject, years before their deaths, and concluded that Kirby "...definitely did not do full breakdowns as has been erroneously reported about ... the first 'Iron Man'. [In the early 1970s], Jack claimed to have laid out those stories, and I repeated his claim in print – though not before checking with Heck, who said, in effect, 'Oh, yeah. I remember that. Jack did the layouts'. We all later realized he was mistaken. ... Both also believed that Jack had contributed to the plots of those debut appearances – recollections that do not match those of Stan Lee. (Larry Lieber did the script for the first Iron Man story from a plot that Stan gave him.) Also, in both cases, Jack had already drawn the covers of those issues and done some amount of design work. He came up with the initial look of Iron Man's armor ...[16]"
Heck himself recalled in 1985 that while some sources claimed then "that Jack Kirby did breakdowns,"
"...that's not true. I did it all. They just didn't bother to call me up and find out when they wrote up the credits. It doesn't really matter. Jack Kirby created the costume, and he did the cover for the issue. In fact the second costume, the red and yellow one, was designed by Steve Ditko. I found it easier than drawing that bulky old thing. The earlier design, the robot-looking one, was more Kirbyish.[9]"
Heck was the artist and co-creator of several new characters in the "Iron Man" feature. The Mandarin debuted in Tales of Suspense #50 (Feb. 1964) and would become one of Iron Man's major enemies.[17] Hawkeye, Marvel's archer supreme, first appeared in Tales of Suspense #57 (Sept. 1964),[18] following the introduction of femme fatale Communist spy and future superheroine and S.H.I.E.L.D. agent the Black Widow in #52 (April 1964).[19] He drew the feature "Iron Man" through issue #46 (Oct. 1963), after which Spider-Man artist Steve Ditko introduced the familiar red-and-gold Iron Man armor and drew three issues. Heck returned with #50 and continued through #72 (Dec. 1965).
Concurrent with drawing Iron Man, Heck succeeded Jack Kirby as penciler on the superhero team series The Avengers with issue #9 (Oct. 1964), the introduction of Wonder Man.[20] The Count Nefaria character was introduced by Lee and Heck four issues later.[21] Heck, who inked his own pencils for many years, transitioned to the "Marvel method" of doing comics—in which the penciler plotted and paced the details of a story based on a synopsis or plot outline from the writer, who would afterward add dialog—and was assigned the help of an inker for the first time. He successfully made this adjustment, and went on to make The Avengers, which he drew through issue #40 (May 1967), plus the 1967 annual, one of his signature series. He inked his own pencil work in issues #32–37. Heck would return to The Avengers one final time to co-plot and pencil issue #45, with inks by Vince Colletta.
During this run, Heck co-created characters including the supervillain and eventual hero the Swordsman, in #19 (Aug. 1965);[22] the supervillain Power Man, who years later became the hero Atlas, in #21 (Oct. 1965);[23] the cosmic entity the Collector in #28 (May 1966);[24] the supporting character Bill Foster, who much later became the superhero Black Goliath, in #32 (Sept. 1966); and the supervillain the Living Laser in #34 (Nov. 1966).[25] During the next comics era, the Bronze Age, he co-created another cosmic entity, Mantis, in issue #112 (May 1973).[26]
Elsewhere during the 1960s, Heck penciled The X-Men #38–42 (Nov. 1967 – March 1968) and introduced the new X-Men Lorna Dane in issue #49 (Oct. 1968)[27] and Havok in #54 (March 1969).[28] Heck drew, over John Romita layouts, The Amazing Spider-Man #57–64 and 66 (Feb.–Sept and Nov. 1968). Heck would also draw issues of Captain Marvel and Iron Man, the World War II war comic Captain Savage and his Battlefield Raiders, horror stories in Chamber of Darkness and Tower of Shadows, and, once more, love stories, in the romance comics Our Love Story and My Love.[8]
From 1966 to 1971, Heck was an uncredited "ghost artist" on Lee Falk’s The Phantom daily newspaper comic strip,[2] and later on the Terry and the Pirates daily strip.