Sunfire was Uncanny X-Men #64 or 65, not Giant-Size X-Men #1 and The Falcon came just after Black Panther, long before Luke Cage–like 1967 or so.
I don’t think that Deathlock was black when he first appeared, but he’s been drawn more black since. In any case, he never operated before 1975 or so.
Asika—since you’re allowing '70s characters, there was Mal Duncan from Teen Titans who didn’t really have powers, pre-early '70s, IIRC–he was more of a…not sidekick, he was more active than that…a hanger-on? He later got several lame powers (magic ram’s horn, techno-sonic horn, some deal where he had powers, but if he EVER lost a fight, he’d die, the Guardian’s old costume (but not his powers), etc) but that was post-'70, IIRC.
There’s Karen…uh…Someone, (Mal’s girlfriend) who became The Bumblebee in one of the worst costumes ever, but again, early to mid '70s (Poor Mal, not only did his girlfriend have better powers (think “The Wasp” without the shrinking) AND not only did he have a worse costume (in one iteration): baby-blue pajamas with a hood and bell-bottoms) he also had (one of his iterations) had a worse name “The Hornblower” (which provided no end of teen-age Beavis-n-Butthead style humor to my pals)).
Tyroc from the Legion showed up around '74 or so…unfortunately for your timelin though, that should be 2974! (and while he might have visited the mid-to-late '70s once (maybe in KARATE KID) I wouldn’t count him. Even if he did show up in the '70s, I assume you’re not counting time travel stories where a black character goes into the past. )
Blade appeared around '72 or so.
Thunderball was first appeared in an early issue of Defenders–so that would have been '74-'75. (And another bad name—“I am Thunderball! Give me all your money!” / Bank Teller: “Did you say your name was Thunderballs? TMI, guy. I mean, I’m hung, but you don’t hear me calling myself Mighty Dick, do you?”
Never underestimate the power of a 13 year old to find a way to make something sound dirty.)
There was a black supervillianess in Captain America–ummm…Nightshade, I think…very Blaxpoitation look and manner circa 1972. IIRC, no powers, she was a criminal mastermind type, and showed lotsa skin. I think she was actually the first black supervillianess.
And actually, the first recurring black character in a Marvel comic was Gabe Someone (Jones?) from SGT FURY AND HIS HOWLING COMMANDOS–certainly a hero, if not a super-hero.
Regarding THE TRUTH, the major sticking point with me was that I can’t possibly imagine a scenario where racists would ever risk giving super-powers to black people, especially in the context of the early '40s Marvel Universe.
If the powers had been an unexpected side-effect of some other experiment, no problem with belief whatsoever, but the idea was todeliberately give them powers and that’s where my suspension of disbelief fails. I don’t buy it in a real-world context–it would be like kidnappers giving their mistreated, captive prisoners new, powerful, dangerous loaded weapons to test, and I especially don’t buy it in a Marvel Universe context–people in the MU in the early '40s were traumatized by super-types: the idea of possibly creating another Sub-Mariner would have been unthinkable and if their opinion of black people was so low that they’d use them as lab-rats that’s exactly what they would have thought they were doing…
Fenris