What were the earliest LONG rock & pop songs on record?

Are there exceptionally long recorded blues or folk songs that predate these, and inspired Dylan and The Stones?

There are certainly a lot of long (traditional) folk songs, with lots of verses, not sure how many had been recorded by the early 60s. Dylan would certainly have heard more than a few, I would imagine.

yep. two collections of 78s released on LP by Folkways in the 50's - Dustbowl Ballads & the Anthology of American Folk Music - would have been key for the folk revivalists of the sixties and both contain two-part longish tracks, but the limitations on length in recorded music before the sixties mean it's not a very fruitful avenue, compared to live music & manuscripts & maybe radio broadcasts.

so like dylan based "hard rain" on the trad anglo-scottish ballad "lord randall" and it was ten minutes long when he was debuting it live

and he'd be familiar with songs or accounts of songs like this one by pete seeger of woody guthrie: "Then he'd hitch his guitar around and sing the longest long outlaw ballad you ever heard"

surprised the Yardbirds didn't record any epic studio rave-ups