Originally Posted by SB

Another bad myth. In fact, Torque loading a drive strugg;ing to get on plane is worse than anything else. ie: too tall pitch, too many blades, too many people, lol, etc...

i spin mine up to 6100rpm. any other people spin high 5's...few that go mid/upper 6's.

Change gear fluid often and consider using a drive shower,,,that will help the only downside to more rpm....more friction heat.

Why build an engine's peak hp for id 5k, high 5k or 6k and run under 5k ? i don't get it.

but I also don't get why your boat is so slow for the hp/torque as it is. Tuning ? Or the boat itself ? does it not want to move ? I don't know these boats so thus why I'm asking.

Are you still running into detonation issues for the super high compression ?and the knock taking timing out ?

Originally Posted by SB

Another bad myth. In fact, Torque loading a drive strugg;ing to get on plane is worse than anything else. ie: too tall pitch, too many blades, too many people, lol, etc...

i spin mine up to 6100rpm. any other people spin high 5's...few that go mid/upper 6's.

Change gear fluid often and consider using a drive shower,,,that will help the only downside to more rpm....more friction heat.

Why build an engine's peak hp for id 5k, high 5k or 6k and run under 5k ? i don't get it.

but I also don't get why your boat is so slow for the hp/torque as it is. Tuning ? Or the boat itself ? does it not want to move ? I don't know these boats so thus why I'm asking.

Are you still running into detonation issues for the super high compression ?and the knock taking timing out ?

Originally Posted by SB

Found this looking to see what others have been getting for speeds on same model boat.:
https://www.boatingworld.com/boattests/day-runner/

Factory says 58.8mph with the 300HP 350MPI. I wonder how tru this is...speedo or GPS?

Yours is closer to 52-54 mph assuming typical 14-16% slip. You should have a ton more power than that 300hp one.

Originally Posted by Paxtonspeed

I am not trying to run under 5000 RPM, that's why I am asking for input on prop selection, I know it should be turning more RPM than what it is. I would like to be at 5k or a little over if I am willing to push it. If the 5k RPM limit of the Alpha drive is myth, than so be it. The boat has an excellent mid range, even better with this cam than the other. I don't see this cam peaking at 6000 RPM. Maybe in a 350, but not a 383. I have some more ideas, I will get it there.

Originally Posted by Trash

A 3 blade in the 19" pitch regime will likely net the fastest speed. I would suggest getting motor to 5400-5700 rpm.

Originally Posted by Knot 4 Me

Yup, A Mirage Plus would be where I would start. You're gonna wanna carry that bow as much as you can. I used to turn a 19" Mirage Plus with a 4.3LX in a similar sized Rinker ('93 206). That was only 180 HP. I'd still ditch that TB and go with a good dual plane and 4bbl. The only difference between the 5.7L (250 HP), 5.7L EFI (260 HP), and the 350 MAG MPI (300 HP) was the induction. Long blocks/cam identical. That poor engine is sucking air thru a straw. Download a GPS app on your phone to know what your true top speed is. I use JustSpeed.