Re: Rigging a 140 HP
It all depends on the measurements of the pad and step. Keep in mind the water will come off the pad on about a 45* angle, give or take some and it changes with speed. The longer the step (setback) the higher the motor will mount.
If the step is roughly say, 8" to 10" back and 3" to 5" up then mount the motor so the AV plate is at least 2" to 4" above the pad. You'll probably end up higher. Keep in mind the style of prop has a great deal to do with this. That'll give you a good starting point. You don't want the AV plate too low on a pad bottom boat, the handling will be unbeliveably bad. Again, how bad depends on the pad dimensions and shape.
It also depends on if it's a straight step or a pocket. Just for kicks, run a straight edge from the bottom of the pad straight back. From the top of the transom measure down to that straight edge and let us know what it is. I'd bet it's 22" to 23".