The role of the TSU Toronadoes in all of this shouldn't be under-estimated. The Tighten Up rhythm is a cornerstone of much Crossover and is a key factor in the transition between the sound of typical mid-sixties soul and what was to come in the 70s.
Think of the amount of great records which owe a debt to that patented bass, drums, guitar interaction: Benny Harper, Frederick Hymes, Natural 4, Carmelita and on and on, quite apart from the great records which the Toronadoes would have actually played on for Ovide and other labels in their own right.
I never tire of hearing their stuff because it's so musical. There's always something in there that sounds fresh and exciting.