1981 Campion Christina 180, Volvo 280, leg 14x23 aluminum prop behind a SBC 383 with 350+hp.
Just getting the engine broken in about 11 hours. When I take it up to 4000 rpm dead stable at 48 mph. When I get to 4100-4200 at 50 mph the boat wants to pull hard to the right . Any suggestions?

Thats the prop torque pulling. Try trimming up a bit.

Volvo 280 no trim. Have bennett trimtabs. I can trim it up a bit by moving the trim bolt one hole and adjust with the trim tabs if needed. I am currently running the middle hole.

As long as you can still get on plane alright, that would be the way to go. You may even pick up some speed on the top.




Darrell.

No problem getting on plane with the outdrive trimmed to the back hole with a stock 350, so should be easy with the built 383.
I am also converting my 280 to a Duoprop. Will have the lower ready to install on Friday. With a prop spinning each way prop torque should go away???

With the duoprop lower installed I have no more prop torque. Boat runs straight and true. Has the hole shot of a scalded cat.

Did the top speed change at all?





Darrell.

I am not sure what WOT is because the engine is not fully broke in yet, and has only about 7 hours on it. But at 4000 rpm it was at 48mph with the single prop and is at 45.5 with the duoprop, so I expect a few mph slower with the duoprop. I will take that as I have solved the prop torque problem, which was unsettling to say the least.