4sp vers auto shaft length

The 4 speed shaft is longer, but the slip yoke for a 727 and a post-'66 833 is the same (30 spline). The 904 and pre-'66 833's use 26 spline slip yokes. U-joints could be 7260 (small, 2 1/8") or 7290 (big, 2 5/8"). http://www.brewersperformance.com/history.htm