So what is the difference between the two. How do they effect the boat performance.

May need a Lil more info..... Are you talking about running surface angle? SmallBlock Heads? Props? Etc..

I know the difference... It's three degrees.

If your talking about transom deadrise the lower the number the quicker to plane and the less power you need to go fast BUT your ride quality will be really rough in anything over 1 ft chop. Most offshore boats are 24 degrees because it gives you the best ride quality and most offshore boats have big horsepower so you get the best of all worlds--of course more length helps tremendously with ride quality too especially if we are talking about truely going offshore.

Personally I would NEVER buy a boat with less than 21 degree transom deadrise (thats the drop dead number for me).

Prop Rake?

That would be my guess as well.

sorry about that yes i am talking Props. i have been looking at props for sale for #6'S and some say 15 and some say 18 degrees of rake. What does that mean? And how does it affect the boat

it effects the bow lift,,more rake* the more bow lift..

ok. so what the benefit or detrement? the boat becomes loose? less trim required? why do you need more rake assuming that you have enough bow lift already.