The 4.3 part should not be a huge deal.
What year roadmaster? Does it have a computer? I have been exploring a 4200 inline and know that a stand alone computer is needed. There are a couple of companies out there that sell stand alone computers if you need one. From what I am told, programming them is the only hard part.
The 4.3 is a pretty good piece of hardware. The turbo boys can do some pretty cool stuff with them.
