Hello, after looking at all the common reasons for my old Nova XL 's lack of speed at WOT. I'm left without real concrete sources for this , except everything is old and somewhat worn. It all works very well but performance is not impressive. So, is the best value in your opinion, a top end kit? Changing the engine for a 502 or just buy a different boat. The caveat there is we love this boat, so that's not our favorite option but an option just the same.
It has a 454 330hp, Bravo 1. Thanks

First question... what are your performance goals to be happy?

Look up Kidnova and his writings. Typings. He went to a ZZ502, modded that one, tried all different props and such, and then built a 557 solid roller motor.

That guy was wacko but still alive :Hi kid. Lol.

The cheapest way to increase performance

or,
put a performance goal and budget together for your current boat. Then double the cost and move your speed increase expectations to 1/2 of what you calculated.

I’m not familiar with the Nova but believe it is more of a heavy family boat?

If you want more performance it’s always easier and cheaper to buy another boat, and you’ll get more money out of the Nova’s stock configuration.

You can spend $10k and months rerigging the fuel and oil system for another 100hp which may get you another 5mph?

But to answer your question, play with props. BBlades has a loaner program where you rent the prop for a couple of weekends. Some people have found another 5mph that way.

Sell your reliable setup, un modified. Someone will want a turn key family boat to get into boating. Then determine what you want to spend, and find a faster hull that meets the criteria. If you invest money into the Nova, you will never, ever be ahead. I am sure you will get the same response from just about everyone here on offshore.

Things to think about.....if you swap motors, next year you will want to fix interior, then touch up paint. You will find that the new HP isn't loved by your old drive, and then you will be pretty much rebuilding the Nova XL. And then you will have a really nice Nova XL, with a ton of money into it.......but it will still only be worth what a Nova XL brings money wise....it won't be the leaps and bounds and $ that you dumped into it.

Sell and buy a faster boat with the power and speed you are looking for ....you will be waaayyyyyyyyyy ahead

This might move the needle at WOT!

Fast, Cheap, Reliable. Pick two.

for how long until the bottle is EMPTY!

Until the engine blows...