68 C/S here - I'm also installing the Borgeson power steering unit. The adapter kit HW2913 will not work with the Borgeson unit. It makes the column WAY too long. I adapted a 3/4 - 36 spline connector and the column is still too long.
So I called IDIDIT - and they said they've found out that the 68 column needs to be a full 1" shorter for a Borgeson install. Back to Ididit for a $75 fix.
The column is Nice and works as advertised for a stock car.