Well my 540 is at Precision Marine in Lousianna and the first numbers back that I am hearing are 650+ hp and 700+ ft/lbs of torque.

nice That should keep it fast Jamie / Lakeside

What do you think Jamie? maybe 88-90. Brian got his 27ZX to 88 on similar power.

Trying to figure out a prop, any ideas

Hard to say for sure, But I will take a guess and say at least about 83-85 gps in fresh water, 84-86 in salt.. The higher torque will be of help to get the speed too. My 625 got about 80gps depending on the prop (ran depending on water 30B1, 30 Maximus).. The maximus was actually faster but didnt alwasy plane as well on this hull.. If he has or raises the X he may get a few more mph depending on where he is currently at.. Jamie / Lakeside

I would hope that it is faster than that, as when i bought it with the stock 502 and the procharger running 5psi of boost, I gps'd it at 80mph. I would think I will be closer to 90 mph.

Well, maybe if yours is a lighter weight 26zx hull. Some of the earlier one were. I know mine & quite a few of the later ones were pretty damn heavy compared to some of the earlier ones eventhough I dont ever remember them advertised as such.. I guess you will find out for sure once you get it installed & test her out.. Keep us posted. J

I would use a Bravo I as a baseline. Probably a 30 for you. If you have a lighter ZX I am thinking 88. Brian Rose has a lighter version and that does make a big difference.

Like Jamie said, you may benefit from raising the drive height. I did not do that because I would have to use a 5 blade to get it out of the hole. I am not ruling out the 5 blade for mine but wanted to get to know the boat more before I asked more out of the drive.

I will probably not try to squeeze any more speed out of mine. To really drive it over 90 you really have to watch out for side wakes. It is pretty hard to keep up with the gauges and do that at the same time. Getting it out of shape at 95 mph is a pretty crazy ride. It runs like it is on rails until it gets upset. You have to get the tabs and drive just right. I got 103 mph out of mine. It has more but I am not sure I have more sack.

It is a great 85 mph boat. Faster than 85 is not absurd but you really have to stay on top of it.