Looking for anyone that has actually put extension boxes and shorties on a 30' Sonic - Boat is a 1996 30' with Merc 502 (550HP per side)...friend is wanting to get some additional speed out of his boat, besides pumping more HP's to it....Anyone that has done this please let me know results.

Anyone???? Have input...

i put 1" and 2" shorties on a 1995 with around 550 hp no boxes though. The boat gained 2-3 mph went from 80-81 to 83-84 but I lost the mid range cruising speed. The higher drive wouldn't carry the bow lost 2-3 mph. How far below the bottom of the boat is his drive, mine is about 6 3/4". Sonic raised the drive by 1" but I think it was in the late 1990's or early 2000's.

I'm guessing about the same as yours??? I have not done the measuring. I do a lot of poker runs with him and he's wanting to pick up some speed...just not certain there is enough there to justify the cost.

What is he getting out of it now ? What RPM's is he turning and what props ? Does he know the weight of it ? Keep me updated about his set up it's always good to have a lot of information so you aren't trying to reinvent the wheel. Did you see the pm I sent you ?

There was a guy on these boards that had 575's in a 31 that was quite fast. Cant remember his name? Hopefully he will see this and chime in. I used to follow his threads on his testing and upgrades.

Teamsynergy used to have the 575 boat. He didn’t have shorties or boxes. Just LOTS of power.

Thats who I was thinking about.

Dano did a lot of experimenting with a 575 31SS. Do a search, there were a bunch of threads.