"Any inboard will throw a bigger cleaner wake than an I/O" I've heard people say this so many times on this site and it always bugs me. Its just not true. Where your propulsion comes from has very little to do with the size of your wake. Displacement (weight), the shape of the hull and speed do affect it. So no, your 1985 Centurion Trutrac III does not have a bigger, better wake than a 9500lb Chapparell.
By the way, I've had an I/O and I've had at least 10 inboards. Would I buy another I/O after owning a wake boat? Probably not. In the 5 years I owned my I/O I replaced the outdrive 3 times, the floor, got horrendous gas mileage, horrible handling in chop, tons of bow rise and cheaper construction, but it did have my favorite wake out of all my the boats I've had. (with no ballast needed cause it already weighed the same as a school bus. I then bought a couple mastercrafts that I added 2500-3000#'s of ballast into and still couldn't get as good of wake out of. Over the years I've owned 5 mastercrafts (yes I dug my X-star) a nautique 210, a malibu sunsetter, 3 tige's and my 1987 Aeroglass 210. Inboards have tons of advantages, but some I/O's throw massive wakes, that you can dial in with trim adjustment. If you're gonna hate on them, hate on them for the right reasons.