When I had my 85 D100 years ago, I remember the wheel pattern being more like a 5 on 4.5. Best this to do is measure what you have. At least that way there then, you'll have a starting point. From there, I would look on craigslist for those year trucks and just ask them what the bolt pattern is and/or head to your local junk yard and measure the trucks that they have there.
Tim, Heather & Elizabeth
06 Street Glide - cruiser