I have a '71 442. This car has th400 and air. Didn't most of these a/c cars come with the same rear axel ratio? Was it a 3.08? A turn of the back wheel gives about that many turns on the driveshaft. Thanks for any advice.
Mike

 

Mark the drive shaft and count the number of revs for 10 turns of the wheel. Thats more accurate than trying to guess. Over a larger number of turns, the ratio becomes more clear. You could have 3:08, 3:23 or 3:42. If you have a TH400 you probably have a 455 too. I'd bet you have a 3:08 or 3:23 set of gears. Post the results.