I recently heard that the Rambam holds that Halacha is like Talmud Yerushalmi not Bavli, when there is a Machloket between the two. I would like to know where this is brought down. Any leads will be greatly appreciated.

The best place to start is Rabbi Dr. Isadore Twersky's monumental book "Itroduction to the Code of Maimonides" (Yale University Press). Rabbi Twersky ztz"l, son in law of Rabbi Y. D. Soloveitchik ztz"l, was a great talmid chocham and historian. In the book Rabbi Twersky examines the often made claim that the Rambam favored the Yerushalmi.