For Orange Sunshine -
except for the main shafts, reluctors, and pole pieces every internal part of the V8 HEI will interchange with the Inline model. This includes the module, coil, rotor, and the advance weights springs and bushings. The vacuum advance units are also completely interchangeable BUT they come in a bunch of different advance curves and diaphragm spring tensions so you can spend a lot of time learning about which one will do what or the easier way is to buy an aftermarket performance vacuum advance unit that is adjustable. I'm pretty sure Crane and Edelbrock both offer the adjustable vac units and they're around $20 - $23.
Just some advice before you dive into one is work with one thing at a time. Don't make all sorts of weight and spring changes and toss a vac unit into the mix at the same time or you'll find it very frustrating and confusing unless you have it on a distributer machine and have time to sort it out.
Mike
