My new SBC 400 is turning 5200 rpm at WOT with a 14 1/4 x 20 SS prop. My engine builder dosen't seem concerned with this as his Busch motors can turn over 10000. I really don't want to kill my Alpha 1 so I have been spoon feeding it the throttle. Which is harder on the outdrive: high RPM's or more prop?

I ran a 11.25:1 compression solid roller 355 ci with a 150 shot of NOS with an Alpha SS and never had a problem. We turned 6000 RPM on motor and 6500 RPM on the NOS. The Alpha does a great job on small, light boats even with pretty decent HP. I think a 21' - 22' boat is about the largest I would want to run an Alpha drive on with a modified motor. As Sutphen said keeping the boat in the water is also critical for these drives survival.

Craig

I am running it in a 20 ft. Wellcraft which weighs over 4000lbs. She will do 60 mph at 5200rpm. I don't usually run her that hard but it is nice to know she can. I try to save it for outrunning storms or the occasional innocent pleasure boater.

Had a modified(heads, crane cam, holly800, CMI) 86 bbc in Wellcraft Nova 23, used big prop 23' after engine rebuild w/heavy cup flying in the bay, damaged upper gears in 1991. Had outdrive rebuilt, switched to hydro 21, ran 5200 for another 14 years no problem with outdrive. I think the key (as stated in previous post) keep really low idle during shifting,check and change drive frequently and during re-entry when flying on top of waves, don't be too agressive with torque upon reentry...high abusive torque kills them. Loved my set up-light slim drive works well if treated kindly.
Good luck

Agreed.... treat it nicely and it'll work fine. Heavy boats and lack of control are what kill these drives. I'm spinning a 25P Mirage Plus with a 383 in a 4500 lbs (loaded) boat and so far it's holding up nicely. I'm turning 5800.

Really over 10k RPM ?

HEAT!!!! will kill an alpha.......put a Simrek drive shower on it......ESPECIALLY if you do continuous running on plane.......doug

They are running a shorter stroke but he says that NASCAR limits them by the new gear ratio regs. Have you ever seen a computer crank balancer? Way cool stuff!

I wouldn't worry just be nice... I run 550+ hp 383 in a 18.5" powerplay. spin around 5800-5900 rpm. been reaming the crap out of it the last few years, no problems yet. Run a sirmek drive shower with 12 outlets and I also made the holes bigger...

nope , Ya got a pick??


I did see a fake dry sump pump once .That was a pretty cool idea. They were running a electric oil pump for the motor before they got caught , free horse power

Rob