I remember a house ad for this, wonder if it's in the issue?

This was a 68-pager, and while I don't think it was the first in this format, it was part of multiple revamps for the title. From 1979, Adventure Comics #463, cover by José Luis García-López.

The opener, "Urtumi the Image Eater" is an oddball one for the Flash, as returning from Earth-2 he's attacked by a bizarre creature, which had been released when archeologists removed a Native American tablet. (Story by Cary Bates, pencils by Don Heck, inks by Joe Giella.) "Mind over Murder!" is a bit more substantial, as Deadman tries to use a somewhat-unhinged scientist's invention, to create a new body for himself. It doesn't work, and Boston continues to get irritated by Rama Kushna, who tells him that would never have worked, and he should be grateful for what he has, because he might have it for eternity...I think Rama was trying to be encouraging, not threatening, but Boston doesn't really see it that way. (Written by Len Wein, pencils by José Luis García-López, inks by Frank Chiaramonte.)

"The Night of the Soul Thief" opens with the Justice Society on the trail of Batman's true killer, and both Dick Grayson and Helena Wayne are unmasked, as their secret identities had been exposed in the wake of Batman's death. The team fights assorted elementals, before being taken before one Fredric Vaux, a sorcerer plotting to end the current age of heroes, so the ongoing conflict of Order vs. Chaos could get back on track, with Chaos victorious and him ruling earth in its name. Vaux had wanted to erase even the memory of the heroes, but too many people in Gotham City remember Batman for that to go away easily. Helena is furious that her father died for nothing, a pawn in a larger game; but on losing Vaux is discarded by Chaos and seemingly done. Doctor Fate then uses what was left of his spell, to convince Earth-2 that Batman and Bruce Wayne had both died, but had been separate men, saving Robin and Huntress's identities. (Written by Paul Levitz, pencils by Joe Staton, inks by Dave Hunt.)

"Climax" is an Aquaman story, and I may need to take a moment to see if he (or Flash or Wonder Woman, for that matter) had his own title at the time: I feel like I've read several Aquaman stories in Adventure. This month, it's Aquaman vs. Aqualad, Mera, Vulko, most of Atlantis, and capitalism! Universal Food Products had entered into a manufacturing partnership with Atlantis, which everyone thought would be good for everyone; except for Aquaman, who had discovered UFP's generators were heating the sea to unlivable levels, while their fertilizers were going to deplete Atlantis's farmland. Or farm-waters; I'm not sure how it works. Arthur wasn't currently the king, and everyone seems to think he's just being stubborn; but come on: the UFP guys had a boat commander in a very Nazi-style uniform, with a friggin' monocle. Pretty sure they're the bad guys, man. Aquaman exposes them, but admits to his friends he didn't blame them, since he didn't have any proof backing him up. Feels like a trust exercise they failed, though. Also, is it my imagination, or despite having less rep Aqualad threw down with his mentor more often than Robin or Speedy did with theirs? Yeah, Robin would've been a good soldier at the time; but I guess Speedy and Ollie probably rough-housed all the time. ("Put down the needle, Roy!" "Make me!" "Put down the chili, Ollie!" "Make me!") (Written by Paul Kupperberg, pencils by Don Heck, inks by Joe Giella.)

Bees. My god. It's Wonder Woman vs. "The Insanity Swarm!" Intelligent bees attack the Houston space center, leaving those stung as mindless and comatose. It's old JLA baddie the Queen Bee, who, when wrapped up in Diana's magic lasso, explains she had taken their minds, but even the lasso couldn't force her to give them back: she had set the self-destruct to prevent even her doing so. But, if Wonder Woman became her slave, then maybe...(Written by Gerry Conway, pencils by Joe Staton, inks by Frank McLaughlin.) 

 This was around DC Implosion time, wasn't it? But, there is a US Postal Service Statement of Ownership this issue: total paid circulation, single issue nearest to filing date, 91,693. As usual, those would be blockbuster numbers today, but I don't think were amazing for the time, maybe even for a bimonthly book. Still, this didn't have a copy of the house ad promoting it; not because it would've been redundant, but this book was no ads at the time! I'll add said ad the next time I stumble across it.