Here's a link to step by step guide to tinker with your 7.4 and the source is very reputable. It's just the cost that get's in the way.

http://forum.grumpysperformance.com/...hp?f=69&t=2900

Airjunkie your pm is full

Rebuild to stock, or bite the bullet and spend the coin to do it right.

Rebuild to stock and sell the boat. Then go buy yourself an outboard powered allison or stv if you want to go fast on a low budget.

I can relate 100% to this. Bought a mirage 232 Trovare with a 330 7.4 and planned to modify it after reading up on what was involved... Long story short I decided to buy a much faster/safe hull and install a big hp N/A setup in that. Best decision I've ever made to switch boats. Might not be what you want to hear, but it's true.

I use to have a 96 208 islander with a 330hp and it would run 70 mph stock. If you spent all the money any put 500 horses into it how fast will you really go? Maybe low 80's? I don't think it would be safe at much more than that.