bwatson1189

Any other preventative maintainence or issues I should look into on this model boat, other than typical i/o boat stuff?

Powerquest_Baby!!

Oddly enough the 330 only puts out 295 hp at the prop and the 365 puts out 350 hp (at the prop). Its still only 55 hp but I know the heads breathe much better (larger rectangular intake and exhaust ports). They also have forged internals which is why you can spin them up to 5000 rpm without risking damage.

Biggus

iTrader: (1)

My neighbor has had a 250 Sport for many years. His came stock with a 454 Magnum, ran just over 60. We installed an M1SC Procharger and boosted it to 77 mph. Then installed a new 510" 8.25:1 motor with an R-Tech Supercooler and got it to just touch 90.

The 250 Sport really comes alive with more power but has some evil traits when the speeds get over 80.

btw, another guy on our lake had one with a 330. It was a slug, ran low 50's

Years back, Trailer Boats Magazine did a test on the 250 Sport where they started with base power (small block) and installed several big block options. It was interesting how well it responded to more power. That hull has a small pad, more hp lets it run much more efficiently up on the pad.

AIR TIME

ext water pick up, also check your plugs to see if any are wet fouled that also causes rpm loss and give a rough idle.

Tibbstoy2

iTrader: (1)

You should see much better than low 50's with a 454 330hp... as I mentioned - my boat ran 60-62 for 10 years... and even faster with headers, intake, and carb upgrade after that. For others to be getting low 50s indicates a tuning issue or prop issue IMO. Just my .02 though...

gsxr1216

i have a '90 sport 250, it had the 100% stock 454 MAG when i got it, IMO the boat is no mid 60's with a 454 MAG, mine was MAYBE 61 tops on its best day on the GPS.

i rebuilt and modified the motor and it made a touch over 470hp on the dyno and it now runs 69 on GPS. with the right prop it will probly hit 70. so with a 100+hp increase i got about 8mph.


low 50's with a 330 sounds off to me for a 250 sport, one of my buddys has a older 25 oulaw with a reg 454 and it runs 54-55 on GPS. the hulls are pretty close on both boats.

AIR TIME

back in the 1990s there were no gps. all speedos which are off anywhere from 3 to 5 mph.a 365 mag sounds right about 61 to 63.330hp motor 57 to 58 gps. speedos my friends were at 65 with 365hp with both 250s running 23p mirage props. my 240 was 62 with the 330hp but I went to a merc 502 after 2 yrs reading were 68 to 70 with a 25p mirage.that was speedo. best with a gps was 83 and climbing with a 509 650hp and 2'' shortie.

SidneyW

I have the exact boat.When i bought it 4 years ago,it had a engine in it that was supposed to be 466 hp. the very best i ever got was 61 on gps with a23 mirage. built a 500 hp 468 roller motor turning a 24 pitch Bravo 1. now i am at 70 gps. these hulls are very hard to make fast. hope this helps. your speed sounds about right. These boats ran 55 to 58 from factory.