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How many HP a 290DP can handle

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glastron24css92

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"I have a 1992 Glastron Carlso

"I have a 1992 Glastron Carlson 24CSS with a 290DP outdrive with C7 props on it, hook on a fresh 496 stroker, around 500hp,625lbs of torque approx. The engine is not done yet. I was woundering how many HP those outdrive can handle???

Tanks!"
 
"Years ago I spoke with two di

"Years ago I spoke with two different factory volvo penta reps on two different occasions to ask this about the 250 drives. At the time, I had a concern. (long story/I won't go into it)
Back then, the 250 model designation had a relationship to horse power re; the number (250).
I was told that this drive would handle bursts of up to 200% of that rating.
Since those days, the transmissions have undergone an increase in the drive gear "shaft" diameter, a slight increase to the gear size, and the two "driven gear" bearing size has increased..... the lower units are pretty much bullet proof!

Your saving grace is that your boat is not a large boat.
You should be OK.

However, something you may want to consider: if your 290 DP was the 1.95:1 over-all ratio prior to this new engine......, you really need to change to the 1.78:1 over-all ratio, of which involves a change of the lower unit only (the transmission stays the same).

The lower unit "drive" gear becomes larger, and the two "driven" gears become slightly smaller..... this equates to slightly more tooth contact in the lower unit.
(ask a 4WD off road enthusiast what he's encountered when going to an extremely low ring/pinoin gear set)

Do the math, and you can see the bennefit of the taller ratio for the stroker engine and the gear strength from the 1.78:1 ratio gear set.

Hope that makes sense to you!

."
 
"I would not be concerned abou

"I would not be concerned about what the drive can handle, but rather the hull

Per Glastrons Specs for that boat...
"This boat may have come with the following or other engines :
(In the interest of safety, never exceed the manufacturer's maximum horsepower rating for this boat.)
230/260 hp
300/330 hp
350/365 hp "

I have a 23 ft Chris Craft Lancer which is a simular hull. I'm running a 260 HP 350 CID engine on it. It will do 40. I had another Lancer (identical) and as the boat's speed got above 42 MPH, when I was alone with no gear and empty tanks, the hull started to porpose. This is not a good thing on a recreational boat (regardless of the ocean racers and the Miami Vice opening sequence).

I would speculate that with 500HP on that hull, unless you are running on absolutely flat water that you will have a monster... and not in a good way. Make sure your insurance is paid up. That is if anyone will write a policy for you with that engine.

I boat on waters that often run a 3 to 4 ft chop
and I will tell you from personal experience that much above 20 MPH is PAINFULL... even with a deep V hull. If you look at all the hot sport boats, you will see that they are "long". Its for a reason. IMHO, a 24 ft boat is not enough boat for 500 HP safely... but, it's your boat!"
 
"I was doing 59 MPH with the s

"I was doing 59 MPH with the stock 454, and it was still realy stable, but i was only doing that kind of speed in realy flat water and i'm smart enough for not doing it in rough sea, already try just to test it, not fun at all!! But i agree with you, it will be a monster!!


But for the over-all ratio, i really dont know what i got? is it print somewhere?? or can i get it with the serial number?? i agree with you for the taller ratio, i won't need to rev it to hi to reach fast speed!, at least 70 MPH!"
 
"[b]"But for the over-all

""But for the over-all ratio, i really dont know what i got? is it print somewhere?? or can i get it with the serial number??"
The over-all ratio will be stamped into the propeller shaft bearing carrier, just ahead of the ring anode.
Remove the anode and wire brush this area..... you will expose the ratio.... It will be good if no one has changed the gear set over the years.

"i agree with you for the taller ratio, i won't need to rev it to hi to reach fast speed!, at least 70 MPH!"
Well, this isn't agreeing with me...... It is what Volvo Penta recommends for any of the BB engines, and if the stroker develops any torque at all, you will want the 1.78:1 ratio.

I may have assumed that you were going from a SB to a BB. You may already have the 1.78's."
 
"well not really, just with my

"well not really, just with my friends for fun, i just want something fast, i have been owning that boat for 4 years now and i notice that i had a bad manifold and water was leaking in cyl.6, i didn't take any chance, i pulled the engine out, open it and both rings where stick tight in ther groove on one side of the piston, so i decide to do a big refresh on it! I decide to go with a 496 stroker that is being built right now, something that will last for a while!!
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Glastron 24CSS
 
"my paxton super charged 383 s

"my paxton super charged 383 stroker, with a few other mods is putting out 625 h.p. in the same size boat as yours, other than the fact that it is a glasply, with an alaskan bulkhead, yeah a fishing boat! It will run about 70 knots with about a half tank of fuel in her, thats about 80 gal.
But yeah if you want to get more out of that b.b. just put a paxton on it, it will haul ASS! without a doubt, probley have tha fastest chick magnet on the lake!"
 
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