Orochimaru would not know of Sasori's core nor any other Human Puppet than the Third Kazekage.
Sasori would know only what Kabuto's told him, which during the first part of his genjutsu, Sasori would only learn of Orochimaru's ability to be immortal through changing bodies.
For both Orochimaru and Sasori, we must assume they know the vast amount of jutsu that the anime implies. Orochimaru would know basically all five elements, and Sasori would be able to perform all five elements via the ninja he's collected for Human Puppets (Note that all ninja captured by Sasori for Human Puppetry are of Jounin-level.)
Who would win?
Sasori would know only what Kabuto's told him, which during the first part of his genjutsu, Sasori would only learn of Orochimaru's ability to be immortal through changing bodies.
For both Orochimaru and Sasori, we must assume they know the vast amount of jutsu that the anime implies. Orochimaru would know basically all five elements, and Sasori would be able to perform all five elements via the ninja he's collected for Human Puppets (Note that all ninja captured by Sasori for Human Puppetry are of Jounin-level.)
Who would win?