Whoops, Guess I had a comprehension fart. 90/90 would be no problem with even a 95". I have that with my 95" flattops and later model -06 heads with just cleaned up ports and a Andrews 26, but I would recommend 37's, The build that Don Dorfman recommended. I installed the 26's while still an 88", they have great lowend torque but they flatten out above 4500rpm with the 95". I put a 98" kit in a friends bike 2 years ago, I was told the stock cylinders can be weak and have to be bored perfectly straight , which sometimes they are not from the factory, or you risk thin spots prone to cracking. He wanted them, I wouldn't have. Maybe 97". Aftermarket cylinders are supposed to be made with a better quality steel liner.