21ft ultra deck

1.21ft ultra deck 502 with set back pro dominator jet what will top speed be around was told 75-80 find that hard to believe.
2.502 horse power was told 550ish find that hard to believe also.
3.What kind of horsepower is needed to run speeds of 75 to 80 with the set up stated above..Thats it for starters.Thanx for the help..

Go to the Ultra forum and ask. I was told a 502 should push this boat right under or at 70.

The 502/502 package will push to 70. Hot Boat tested the 21' deck in Havasu and pushed it to 70 in moderate conditions.
You can beleive some of what you hear:D

I think 70 sounds right.
I have a TPR deck, (they were TPR before Ultra) and I had 400 HP in mine and she went 60. My hull is a lot heavier than the new ultras, so 70 sounds right.
I just put in 700 HP, so I am lookin for 75 to 80. In an Ultra it would be faster, I just have a very heavy layup.

The 21 with a 502 should run around 65 to 70 MPH.