For anyone who might need the 550 swingarm measurements, that I should have posted ages ago, here they are.
750 550
Width at pivot 9 1/8" 9 1/4" (installed with cups, may be same)
Between Axle Adjust. 9 9/16" 9 9/16"
Overall Length 20" 21"
Center of pivot bolt hole -
Center of shock mount hole 15 1/2" 16 1/2"
Pivot bolt hole dia. .553" .553" (estimate)
Sorry I didn't do this sooner. Seems that someone, on this site, has told me that the 750 swingarm was shorter and that was why they were using one on their 550. Now, for the life of me, I can't remember who it was. I have an idea but, I hate to say. So, it seems for now, if I want a longer swingarm, I'm gonna have to stretch one. Unless someone has info on one. If so, I hope they don't wait as long as I did to get back to this post. Later on, Bill