Standard-7 splined clutch drums don't have the ability to run the smaller tooth sizes in .325 pitch. I know they can run 325-9 rims but I believe 8 and 7 has no clearance.
Just found this..it should help you with the options: http://www.oregonproducts.com/pdf/sprockets/RimSproxFB0601.pdf
You're the man! Thanks again for all your advice here, I really appreciate it.