Gary Anderson

Jason,
Welcome to the board. Do a search in the Tech Q&A section on upgrading 7.4 motors. There's been quite a bit on the subject. Pay attention to the subject of the 7.4 peanut port heads, they're the real restriction on hp with these motors.
IMHO, that's a big heavy boat. To get 7-10mph more, I think you'll need to drop in 502s.
Gary

mpally

Something else to think about in this situation. You may be willing to sink some money into this hull to get 60 mph. However, upgrading a hull like this will most likely reduce resale value. If that is important to you, I would recommend another boat.

Steet

Jason, I have a friend that has a 1994 SunSport. He has the 454 magnums with thru-hull exhaust and it is very nice. His boat will run around 65mph with the 3 blades and 63 with 4 blades, but actually planes better with the 4 blades which he also likes better. His boat has no bottom paint and stays on a lift in a fresh water lake. It is a very nice boat. Your boat should be faster. These boats are tanks and also have a 9 1/2' or 10 beam. Are your engines 454/330's? He is running mufflers and his exhaust exits out the side.

formula31

Hm, my cruiser may well hit 70 this summer, hopefully any way. Of course, Im nuts.

mcollinstn

Steet,
My guess is that your friend's speed is "speedometer" speed, and not GPS. A buddy has a cherry 1990 311sr1 Formula with 454 mags and it only runs 66. (my 1991 with 502's runs 72).

Jason, $700 for 10mph is not a normal occurrence. Mr D lucked into a good combo with used parts AND only had one motor to modify. Even with his excellent luck, you'd be looking at $1,500 (and prop lift isn't going to get you where you want to be with your long heavy hull).

If you truly want to mod your SS, then bolt on a low boost procharger (4psi). You'll likely see the 7 mph you want and end up close to 450 hp per side.

As far as a gofast with a good cabin, you'll be looking at 35' and larger.

formula31

Yea, Im scared to add up what I have in my engines, hull and drives. One thing to check is to do a speed run, take off the flame arrestors and open the engine hatch some or remove it and do another speed run and see what the difference is. These cruisers typically are not getting enough air down there and the stock 7.4 flame arrestors are not so hot either. Just a cheap idea. I was amazed at the difference it made on mine when stock. I ended up adding lots of forced fresh air and much bigger arrestors. Then I started spending real money, well, credit anyway.