any tire/wheel advantage to upgrade axles

Just went through the same question and there are more tire selections at 15 inch than 14...and I was going to get axels...do the brake shoe thing and rear drum...BUT.......found out 15 inch small bolt pattern wheels are available and I found a pair(used) that are 8 inch with a nice offset...My 72 Demon now has 275/60/15's on the rear...rpm's are lower at any speed and I like it alot....summitt has them..also jeggs..(alot cheaper than the other way...axels...drums..brakes...etc)