Please help. Slant 6 3 speed to 360 3 speed z bar help

Thats alot more than im trying to get into at the momant for my budgit im just trying to figer out how much i need to cut off my /6 z bar. Im running a 360 with a 10 1/2 ince bellhousing to a 3 speed a body trans. Thank you tho