At lake Elsinore for the weekend. Woke up early to hit the water before it gets too choppy. Made a run and the gps says 56 mph.
The boat is a 73' Howard custom with 455 olds, high rise manifold and Berkeley pump. I have no idea what impeller is in there but assume it's stock.
Question is; is this a normal speed or should I expect more. I don't think my throttle cable is opening up the carb completely because of the angle of pull, but there is not much left to go.

The guy I got it from told me it was a 65 mph boat and I hear people saying they are doing 75+. Not a big deal, just wanted to make sure there was nothing wrong. It feels strong when I go.
Thanks for the reply

I think you should be extremely happy with anything over 60 with an Olds.   I sure hope your oil pressure gauge is working accurately.   I don't thing there is anyone on this site running north of 70 with a 455, but I could be wrong.   Mine will top out at 45 but I am moving a boat the size of a small apartment.

your doing real good for that rpm

yeah i am doing 40 at about 4000 rpm...  lol  my oil pressure consistently stays between 50 and 60

yeah i am doing 40 at about 4000 rpm...  lol  my oil pressure consistently stays between 50 and 60

Yessir id check the oil pressure issue, because it does sound to me like an issue. 20-40 sounds too low to me.

your doing real good for that rpm

let me re-state, your mph seems good, however, the oil pressure does seem low

Another good addition for any 455 olds would be an oil filter relocation kit. From my own expirience, because the oil filter is bigger on the relocation kit you can hold another half a quart of oil more.

My first boat was Olds powered, my best number on the GPS was 67mph. I beat quite a few 100mph boats with it. I wouldn't believe everything people tell you about how fast their boats are. Seeing is believing. As far as your oil pressure, what quality is your gauge and did you install it new? Not all gauges and sending units are accurate. I find that keeping an eye on your gauges for changes is more important. Example, it always runs 40psi on your gauge and today its running 35psi, this would indicate a problem. Same goes for temperature.

I believe it is the original gauge from 1973.  It has always run the same numbers from what I am aware.  I do see your point on that.

I don't think there is anything wrong with the motor, it sounds great and seems to have good performance.  It has a slight hesitation if you stomp on the gas but I figure that is just a carburetor setting or the vacuum advance on the distributor (I know I should get rid of it).
My only concern was that this is my first jet boat and I don't know if that was a good speed, especially when people are "running" 70mph.  Sounds like it is fine and I am no longer worried at all. 
Thank you everyone again for the responses.

Oh and I do have the oil filter relocation already on the motor.  It's relocated to the transom.

Can i borrow a gps?