The more I think about this subject the more I would just leave your boat as it is. Your boat is going to be pretty quick with a 330 in it. It's a fairly small boat for that kind of power. Sure with a bigger engine your going to go faster but there is a limit as to how fast a 20 foot boat should go. IMO 500 hp is just to much for a boat that size. Things can happen fast and a boat that size can get dangerous in a hurry. Plus to get 500 hp your going to spend close to $10,000. Trust me I know, I've done it and I got a lot of good deals. Which I have to say have kind of dried up over the past few years. So if you take your boat and sell it when your ready for more speed, take that money and the money for the other engine you'll have $20,000. For that kind of money you could buy a much safer, faster boat. I know it's not what you want to hear but it really is the smarter route. If you take a $10,000 boat put a $10,000 engine in it your still have a $10,000 boat. You'll never get your money back when you decide to sell it. If you must have more speed, find a nice stock 502 to put in it, it will be easier to sell later and you'll have far less into it.

Oh no........here we go again.

Endeavor32 valid point all the way around but the more time you spend thinking about what direction is the best financially the closer you get to realizing boats and speed equals parasitic financial loss.....lmfao.....I agree it's a good idea to keep in mind the value of the boat when considering upgrades which brings us back to a few cost effective modifications that produce proven results. If a guy wants to drop a few grand to make more power or 10's of thousands to make lots more power that's up to him. But once again you have a very valid point

https://www.youtube.com/watch?v=xL5cyKdWnF0 Crazy ''Wette Vettes'' old 210 Baja with a 496 stroker making big power. This wasn't a little 9:1 deal that's for sure.

I agree to a point 500 hp might be to much for the boat. I cannot go to a bigger this is about the biggest I can buy reason being is that it is getting pulled behind a 38 foot 5th wheel witch is being bulled by a 3500 maga cab dually. yes I know I am way over the legal length only by about 10 feet lol. The truck is rated to tow this weight plus more, back to the boat... I don't think It is going to cost me 10g's for a 500 hp 454 done right. I just cant see where all the cost comes from but I could be wrong. The 454 I have as a spare has all forged internals witch is a good start. I was going to put a set of heads, intake and cam and freshen it up. drop that one in and let her rip. what kind of top end do you guys that this boat will have with the 330 55,60,65......110 mph.........................................

I agree the Edelbrock Marine heads aren't as good flowing as a Dart, Brodix, or AFR of comparable size, but they are much better than a stock 330 peanut port, and similar, but better, than a GM iron rectangle port.

Everyone I know who's used them, has been extremely happy with the quality as delivered with them, for an out of the box head. For 1700 bucks a pair shipped to your door with Inconel valves and marine coating, they are a great replacement for the heavy GM iron castings at a great price.

http://www.amazon.com/Edelbrock-6155.../dp/B000N8IOHK

Stock 330HP, 70mph. A 21Ft boat that runs 70, is plenty fun. Run like endeavor32 said, and enjoy it as is before you throw power at it.

ya I agree on that, the more I add it up the more sense it makes to just leave it alone do some maintenance items on it. Put some synthechic fluids in it, a tune up , a once over and let her rip. 70 mph is moving along pretty good

MT that video reminds me of my friend that has a 21 ft. Checkmate with a 598 in it....... Some people just like living on the edge.

Demax990 you could always build yourself a good running 454 and stick the 330 back in if you decide to sell the boat and keep the 454 you built for another project.

Oh.... and we definitely need to see pics of that double trailer setup going down the road!

I only have a pict of my 05 duramax with my old boat it is for 2012. when I get the new boat hooked up to the trailer I will take another one with the new set up but it will not be until next year

sorry it took so long but here it is