I am running 300ZX brake calipers on my 71 240Z, so thought I would update the master and booster to a 280ZX setup. The booster that I received, is a monstrous 10in. in diameter. It comes close to covering the clutch mounting hole altogether. What car would this be from? From what I can determine, there are only two sizes, 8in. and one slightly bigger. I found a thread on this awhile back, but can not locate it now. What size booster am I looking for?