Just picked up my new boat she's a 98 30 with 03 300x's. Starts to porpose at approx 60mph and continues to do so until the 80mph mark. Nothing outta control just annoying ? I know a tunnel tab but any other way to cure ?

My 30 with Bravos did the same thing.
Just don't spend much tine running between 60-80.
It what I did.

Throttle up........Adjust trim........These boats have 2 speeds fast and idle..

Bern,
The boat looks GREAT! Best of luck with it. Now its time to change your avatar to "Berns30cat"

You will not stop it. Like Speed2lead said, boat was made to run fast.

i run 50 or 100.......

took her out today for a few hours. seems like in a 1 ft or better chop, once ya hit 60, a little trim and 80% of it goes away. annoying in flat water but then again i havent been using the trim at all til today. was a test and tune day and plenty more ahead. Thanks to all for the input. Robert was good to see ya and thanks for the compliments.

On a flat day you need to be doing 80 and up to get rid of it!

they don't like flat water, you need a little chop to run fast anyway, otherwise it just wants to stick to the water.... i rarely notice the porpoise because it usually matches the chop at LOTO and i just accelerate threw that speed range.... and mine really only will do it around 65-75, but the sterndrives might not be as sensitive as the O/B's would be....

I have the big tab on my 05 30' and use it to 80-85. I don't run the boat on flat water much, mostly ocean running. I ran Havasu last weekend and used the tab till 85 on the flat water. Just a little tab goes a long way at 70-80, then I lift it flat past 80-85. I only used it getting to 85 but I ran the boat at 90-100 all day long never dropping below 90, only when the IMCO ******* tried to take my bow off at 90, guess he didn't like the idea of a 30' with wackers getting ready to pass his ass.
Andy