Et street radials on a 4 speed ?

I have a set of center lines for track use only 15'' x8 was going to mount et 255/60-15 or 275/60/15 street radial have two rears 3.55 and 3.73 will try both . i am going to the track on my BFG 245/60-14 to make some passes so i will know what height tire to buy 26'' or 27 '' height. when i know my top speed and rpm at the finish line i should have a better i dear on height