The band's growing fame would make the wealthy owners of the famous Whiskey A Go Go, located on the Sunset Boulevard, to invite them around late November once "on secret" for a set, it seems the patrons liked it so much that they invited them an entire month straight (opening for plenty of growing acts like The Doors, The Byrds, and so on) so even the big hats were watching their style. Because of this they decided to give thanks to their previous joint place and became for a while the house band for the whiskey bar, this meant no office floor to sleep as they had no house anymore and soon found themselves easy riding on another band's house who was in turn the offices of another bar place, quite the mess and they soon were kicked out because some of the band members, Weis and Ingle, got a nasty habit of drinking and living like braggards. Bushy was seen as a skilled mediator until he couldn't control things anymore (Weis cleaned his boots with his peers' hand towels) and was invited by the offended to quit his band and join the other side, he refused categorically but made amends for an easy transition out by filling their drummer role once.
They had to quit wasting money on luxuries such as instruments and substances to rent a house while having bigger and bigger names on their Whiskey place, even joining on stage (and later backstage) with Dr. Timothy Leary, a very well known name among knowers. Their sound evolved too, being heavier and heavier to the point of parody, they were no longer employed by the Whiskey A Go Go around February 1967 but became a wanted act in plenty of other bars, other than a couple of nights were they played for free to get funds for the bar they first played in and stayed for a while, the Bido Lito.
This entire series of events is written because, finally, on 3rd and 4th of July, 1967, Iron Butterfly opened both for a big concert in Santa Monica Civic Auditorium by The Doors and played stand alone in a famed club called The Galaxy Club, both were recorded but the latter is important, historically, because it's among the first decent audios of a rendition of their Iron Butterfly Theme, called by many witnesses later as the first heavy metal song they had heard. This is crucial because a band up north in San Francisco, Blue Cheer, would start officially taking really loud gigs a couple of months later and released their first album, considered by others as the first heavy metal album ever, on January 16 1968 while Iron Butterfly's song would be released in their first album on January 22 1968, a week later, despite being extensively played before with the first actual proved date of July 4th (3rd too but audio was all busted). Many claim the official version is subdued, in fact Weis recalled he didn't like the album's editing because it was too tame to the actual thing, many for years thought this was to steal Cheer's thunder but decades later (officially in 2014) a recording appeared (webm related) and confirmed that yes, the live version of the song was considerably heavier and easily stepping on Black Sabbath territory, proving witnesses correct all along. Some say Blue Cheer's main man Dickie Peterson had to have seen Iron Butterfly due to him watching The Doors in LA at some point, and the Iron Butt Band did open for them multiple times at multiple places. At least Blue Cheer still has the record for being the loudest enough band first to appear on the rock scene, which is consolation enough for the Iron guys being the heaviest.
Sure enough after the famed Galaxy Club gigs and Civic Auditorium opener, the band was sought hard to sign with someone, Ron Bushy said a friend of his Neil Young of Neil Young fame had just signed with some dudes with inside moves in Atlantic Records (also called Atco), so because of this suggestion they also decided for such move, finally a paper deal. They rehearsed actual songs, which they had plenty, and decided to select some to cut their first recording called Heavy, supposedly made in October but some claim mid-August to early-September, along with an off-album promo single called Don't Look Down on Me which to this day has some claims disputed on who recorded it.
Why the doubts? because something happened, for some reason Danny Weis, the guitar man and only one of the two original members, decided to leave in August and out of nowhere with a contract signed the band got themselves into a crisis. Big part of the sound was thanks to Weis' knowledge and education, the guy wasn't an asshole at least to his friends so he decided to chomp on the last gigs remaining, the band tried to remember whom they had heard that could fit into the very difficult role of replacing an actual pioneer, the rumor started to spread for a while with names like Neil Young and Jeff Beck, the latter who was struggling with the first iteration of his own group and who was a big fan of the band, seeing them constantly after he got fired and ditched in Yardbird's US tour for being a lunatic.