all I will say is I have been in the trans buisness for over 25 years now. The bolt in was only made to repair a case that the outer race had spun loose in.The weak point is the spring,roller and fingers that lay over the bolt in race does not change this.If the factory race is still tight in the case no reason to change.I have a many of 727 behind SB/BB with some stout motors from stock to full manual VB with stock sprags and no problems.The fingers in a bolt in can roll over as easy as a factory unit if abused enough.The one exception is the 16 element ultimate sprag it has 16 rollers instead of 12 and uses a ford c-6 style sring and roller that is a better design.