[mike16]

to go from a 4.11 or a 3.73 to a 3.08 rear you will need more than a ring and pinion. you will have to locate that part the ring gear bolts to. dont know what its call off hand but i looked into it and you'll need that part. another benifit is improved gas milage. my 72 witha 307 2 bbl and 3.73 gear gets about 13 mpg at 55 mph. a frind has a 350 4bb with a turbo 350 tranny and 308 gears. he gets 17 plus mpg.

better to have a pro do it or find a complete rear with the 308 ratio. Pic a part in las vegas off of bolder sells rear ends for 110 bucks drum to drum.