I have a 1988 Z21 Donzi with a 350 Mag and side exhaust. Runs great, starts well,sounds very strong. I run a 19 inch quicksilver S/S prop (WOT 4600 RPM). The boat is in excellent condition and I am very proud of it. It will do close to 50MPH, is this right or should it go a little faster? The reason I ask is looking at the used boat section, boats with the same power/size owners are claiming speeds closer to 60MPH. Is this wishfull thinking or am I running a little slow. I don't know. Any input or comments would be helpfull. Thanks, Jamie