do you own a set of calipers? Lets start from scratch here..
#1 Im more than casually sure that SS cast a cyld capable of carying an 85 bore. The later castings were in fact able to go bigger, 78 for sure and I do believe that there are a few 80s around, but 85 is flirting with a few later model cylds that I dont think these were capable of
#2 VERY FEW of these are setup for a stock stroke. You REALLY need to spend some time with a set of calipers and take some measurments on this.