It's gonna take something close to an 84" belt -- but each car is a bit different depending on pulley size (underdrives change things), position/condition of the tensioner, etc. I bought 3 belts and told the parts store I'd bring back the 2 that didn't fit. I bought, as I recall, and 84.5", 84" and an 83.5" -- and used the 83.5".
The last digits of the belt part number usually represent the length. For example -- 1065 -- 106.5"; 0835 -- 83.5", etc. Be sure for final fitment that the arrow on the tensioner face points to an area close to the middle of the marked 'range' on the tensioner face.