couldnt find exactly what i was looking for in the search, so ill post this if someone else can use the info. calculations are a w/t transfer into coily sierra,might not be 100% correct but close enough. Rpm is final drive, 65mp/h = 105km/h
coily case (left). W/T with 6.5:1(right). both on 205/70 R15
coily t/case on 205/70 R15 (left). w/t 6.5:1 on 31's (right)
coily t/case on 205/70 R15 (left). w/t 6.4:1 on 31's (right)
coily on 31's with 6.5:1= +320 rpm. i could live with that
coily on 31's with 6.4:1= +221 rpm.