with 800 hp a side in a 35 fountain with 6's you would go 120+. for the short boating season we have up north that seems like a awful lot of work for minimal gains. could you imagine going through all that. then prop testing then possibly having to buy spacers for 3-5mph on the top end? to go through all that i would sell the #6 stuff and put arnesons on it. unless your boat has an on-off switch for throttles i dont see it worth all the work. just my opinion. on a 1988 boat i would look into having the hull blueprinted if it hasnt been done before i started reglassing the transom.

Not considering moving them up just for the HP Matt, but just looking for the best set up to make the boat run to its potential. I just feel that its set up conservatively.

Hmmm. So you think that raising prop shaft height from 1" below the bottom to 1" above will only net less that 1 MPH? If that's the case, then obviously Im not going to consider doing all that work for next to nothing.

I would not be doing it JUST for 3-5 MPH on the top end, but also would be looking to gain some cruising speed in the process. Not to mention, practically every #6 boat Ive seen, throws a rooster. Isnt a #6 considered a surface piercing drive? This boat does have a small rooster but only with a bunch of trim.

2" of -X- is a huge change. Zero Patience is right the 17" 4 blades are not be real happy with that set up. Your gonna need more diameter possibly even a five blade to get your efficiency up at cruise.

On the other hand..Just picking up a few MPH would be ALOT easier (and cheaper) by switching the drives from wet-sump to dry sump. That'll free up almost (if not more) 100HP per side. Problem solved. .

I like your thinking Craig! Hahaha.....now if you could send me all those parts that were hidden in your garage to switch them over, we will be in business!....Is it really 100 HP a side when switched? WOW.

Four people, full of fuel, water bigger than it appears and runnin in the 80's.... note trim and tab position

I'll have to do some searching on here when I get some time. I talked with a Merc engineer and he told me how much HP that the 4.5 gallons of drive fluid robs. I wanna say that it was over 125HP. The wet-sumps use up less that a Bravo. I think that he said it took 35 HP to turn a Bravo...

I guess every bodies expectations are different. I have been reconfiguring my Flat deck which has 750's and now No. 5's to run in the low 80's . But what is more important is what are you willing to give up to get the extra speed . In my Case mid range cruising and planing are more important than that extra 2 to 5 mph. Mine is a pleasure boat I will spend more time with fam and friends than blasting wide open . I am starting with my drives at 3.5 below the hll and they 3 inches of spaces , I will space up to find my sweet spot but will not end above the running surface . That being said I will probably leave a few mph on the table but as I said it is all about your priorities. Kreed all I can say is changing your drive height is a Huge job if you do it yourself as I did or expensive if you pay some one to do it. It will take longer than you think and more time than you expect to dial it in . My 2 cents " if its not broken don't fix it "
Rick G.

OldSchool and Zero Patience. Are your props spinning in or out?