Do they all chine walk real bad around 70 mph I don't think I can drive through it.it's a custom 496 with a Whipple 725 hp

Your running to much drive trim. My 288 will run 78 to 80 and the only time it starts to do that is when I get it trimmed up a little to much.

How far is to much trim

Do you have the new hull or old? I know I've been in some old hull 28's and they walked like crazy. My new hull has no walk.

It iS the old hull 2004

Anymore than 3/8 on the gauge and mine starts to wonder a little. It is something you have to mess with a little. What prop do you run on it.

If I put my trim all the way up, mine gets a little squirly. My wife has commanded me "no mas"! My trim at 4 is straight with the hull...but if I lift it more, I gain mph, along with a chine walk; boat is still new to me, so I'm toying and tinkering with different setups in different conditions

I have tryed a 28 and 30 four blade and a 26 p5 hydromotive that worked the best

I had a 2002 that ran about 82-84. I used to drag the left tab a little and that definately helped. Too much trim will make them walk but also make them fast. The more trim the more speed just need to find a happy and safe medium. Hydraulic steering would help a ton too if you don't have it. Mine did not and desperately needed it.

What motor did you have to get you to 82 / 84? That some high-speed without hydraulic steering.