FYI, T- 525hp will push that boat 76mph fully loaded.

Here is more info, thoughts, on the 502 upgrade, I have been mulling it over trying to figure out the best way to get the 500 HP mark, I was convinced the Crockett upgrade was the way to go, but on second thought if you bought a used pair of HP500s and sold your motors you would be about the same money as doing the upgrade. Im looking at it like this, there is a pair of 500s in the classifides for 24k, I got to think your 502s are worth 10 to 12k, so say 11k, now you have 13k plus install in the 500s, and you have "factory" power that I would think make your boat a bit more valuable. And I dont think you would have spent any more money after it was all said and done.
You only have 470 HP not the 525 that Crokcett says you will get, but add some CMI headers and you may creep up to the 500HP mark.

Plus there was a thread, in the general boating section I think, about a guy who had about the same thing done and got only 2 MPH. I think Arizona speed or something like that sold him the upgrade kit, I do know he never had them dynoed, so who knowes how much HP he really got. But I got to tell ya that that tread made me rethink the upgrade deal. I think Im going to lead in the direction of a nice used pair of 500HPs.

Just my 2 cents and in no way am I beating on the people who did the upgrade on the other dudes boat, just telling you what was said.

What ever you do keep us in the loop and good luck

Thanks for the info!