Instant Party! isn't very highly regarded as an Everly Brothers album, for the good reason that it showed the Everlys stepping outside of their rock & roll personas.
Apart from the crisply played and sung opening track, "Step It Up and Go" -- which had been suggested by Ike Everly -- and a few minor bright spots such as "True Love" and "Ground Hawg" (another Ike Everly-spawned track), the material was pretty dire, confined almost entirely to the pop standards of another era, including such chestnuts as "Bye Bye Blackbird," "Autumn Leaves," and "Oh! My Pa-Pa." It was sung well enough, and much of the playing was impeccable, but also, apart from three exceptions, incredibly boring, something the Everlys had never been before.
Instant Party! marked a low point in their artistic fortunes yet, ironically, even as they were delivering it to Warner Bros., the Everlys were recording singles such as "Crying in the Rain," which represented their sound and their work far better.