Any one have a Powerquest Viper with hp500'S. I have a 99 with 30'wheels and am stuck in the mid 70's at 5100. What are you getting.

With 496 HO's and non-labbed Merc 28's I have seen a top end of 81 GPS and have no problems getting 78 GPS in the hot/humid weather here. I only get 4950 RPM and have never seen over 5000 RPM. I will be trying some props to see if 5100-5200 is out there and also to see if I can get to the 83+ mark.

BillR had some perfect Merc labbed 30's in which he was near rev limiter and getting a good 80 GPS. He also has 496 HO's...

Would like to hear form those with the HP500's and the ne 525 EFI.

GPS or Speedo?

All three of us have gps speedos....and HO's. I am also at 78 on a regular basis with my labbed 28's; although, they are on the rev limiter and are soon going back to Throttle Up for tweaking. BillR's merc labbed 30's ARE perfect. I ran them on flat water, in 80 degree temps with high humidity and got 79.7 at just under 5000 rpm.

performancemary, you have HP's in that boat and only hitting mid 70's??? something ain't right!

You sure you have a vYper?

I was asking performancemary hoping the regular speedo was wrong.

That set up should get you 83-85MPH. Are your props "brand new" condition?(no dings, deep scratches, never ran thru mud/sand,never hit anything.)Are your props spinning the correct direction?(Should be spining in on that boat.)Have you checked the "toe" on your drives lately?(Should be about the same front to back plus/minus 1/8th of an inch.)Are your engines tuned properly?(New plugs,cap ,rotor, plug wires.) Have your flame arresters been cleaned out good lately?

Thanks for all the info. I just had the engines tuned, plugs, timing, caps ,the works. The props are brand new lab finished from Merc . The GPS last time out was at 75.2. Haven't tried good water yet. Hope to see some on the 4th
I will try reversing the props. They are turning out now, came that way from Powerquest.
Will let you know what difference it makes. Thanks everyone