When you say converting over to 7/8 -14 dies, I assume you mean drilling and tapping a tool head to accept standard dies. It can be done, but there is more involved than you might think. The end of the sizing die needs to be turned down so it will fit into the recess in the shell plate. Otherwise you won't get full length sizing. Once you drill and tap the the seating station for a standard seating die, there isn't much clearance for the seating die because of the powder slide housing and the tool head anchor screw. On the ones I have done, I have had to reduce the diameter of the top of the die, and also had to shorten it so it would fit under the anchor screw. You also need to think about where you are going to do your case expanding and flaring. It's best if you use a Star expander plug and do it in the priming station. If you don't have one of those, you will have to use an expander die, which probably means expanding in the seating station, and seating in the taper crimp station.....but then you don't have a separate taper crimp station.
I had one tool head that was drilled and tapped for 7/8-14 dies, and I did use it for loading 9mm and 40 S&W for a while, but I sold it once I was able to acquire Star parts. It took a lot of work to get everything set up and working the way it should.
Richard Daniels, I think the same guy your talking about can also turn down dies to standard Star dimensions, though I don't know if he will work with yours.
You can also buy new Star dies from CH Tool and Die. They recently completed about 50 sets of dies in various calibers.
