I've got a tired 200 horse 305 in an 87 Wellcraft 210, 2700 lbs, speedo reads 40-42, what can I expect going from the tired 305 to a 320hp 350? Thanks

47 maybe 50 on a good day

really, ok thanks

woody is about right, hp / speed not cheap or that easy... wish it was


hell no I dont then I wont make any money


at least im honest

what do you think it would take to get it into the mid 50's

Another 120HP more should give you a 8-9mph increase.
You said your 200/305 is tired so a fresh 320HP should give you more.
I know of two boats similar to yours running in the 50s with the new 325HP/350 vortec engines.
A 1984 20' Liberator and a 1989 205 Formula. The Formula has touched 60 a time or two but that boat is likely lighter than yours.

Are you sure that boat only weighs 2700 lbs? My 20 ft Malibu inboard ski boat weighs 2700. However it has a hull and drivetrain made for pulling and only a 260hp engine and it would go 47 when it was new. I'd guess right around 50 for the new engine.

Good Point...
My 1987 20' Donzi Minx weighed in at about 2700 dry. That boat would run well over 60mph with a 270HP/350.
My friend's Formula 205LS weighs in at about 3300 dry and has touched 60 with a new 325HP/350.

Woody, if your boat does really only weighs 2700, it will run close to 60 with a 320HP. But my guess is that it weighs at least 800lbs more than that...

I was just going by this

Well then a 320HP/350 should do you just fine then...