[skatinjay27]

do you already know what brakes your gonna use?
because different brakes will add different sizes to you track width so if you measure from pad to pad then tell the you want that size but then you brakes end up adding .5" to each side you gonna have clearancing problems. and IIRC your rear tires are like 345or 335s right?
that leaves LITTLE room for error esp. on 67-68.
i think when it comes to it its always better for your rear to be to short than to wide since you can always make op the difference with spacers.

o yeah- yes that how you measure it, just take into consideration what i mentioned above.