Yeah , Hyp
A friend of mine has a 20' Rinker with a 406 small block and an Alpha. Been running it two years now and no problems:rolleyes:
And this guy isn't easy on it...I wouldn't run it as hard as he does:cool:
The original MERC 350 MAGNUM (260 HP) did 58 mph , changed to 325 hp Vortec crate motor and got 64/65 but didn't have the holeshot of the 260 because he bought a GM engine that specified "not for highway or marine use" . Marine cams are different:eek: Then went to a 406 sb . Dynoed 390 hp and over 400 ft lbs torque. This got him in the upper 60's.

Good luck Bud.

tssteph
I laughed. I like your thinking. Heck for that matter put a blown 540 in it... REDUCE the intake on the speedo,,, and tell dad it's just his imagination, the boat runs the same as it did last year, You just don't remember cause your getting old.

No need, got the ok.... Itll be a lot quicker this next summer. Maybe if the local with the 29 baja with twins learns how to drive a little better we can have a competitive race, this year i blew him away... He dosent seem to know that to go faster, the props need to be in the water.... Some people.

if your gonna put a small block in it,
you may wan't to switch to a
1.50 ratio, or a 1.47 ratio drive,
V-6's usually came witn a 1.84
ratio drive, and as far as i can
remember, all gear ratio changes
in alpha drives are in the upper
unit, gear ratio's are usually stamped
on the decal on l/h side of upper
gearcase.
you can leave the same drive on,
but you WILL have to buy a MUCH
LARGER prop than you are currently
running, and you will have to
GO EASY ON IT.
good luck,
jt

get yourself a PAW catalog (performance automotive wholesale). you can order it off the net.

They have every kind of engine kit combo known to mankind.

If $$ is an issue, you will obviously be going with a 350 Chevy or maybe a 400 smallblock (they won't be more than a hundred $$ apart). You can get a complete kit with a ready-to-go block all rustoleumed up inside and choose your parts.

A "stock" 350 chev with a decent dualplane and a 650 holley and a marine cam will give you around 280hp. Your drive will handle this just fine.

The 400 smallblock can make 310 inexpensive hp (stock heads, dual plane intake, hydraulic cam).

Keep WOT rpm under 5000 and everything will be happy.

NOW, you will need a V8 oil cooler.
you will need V8 exhaust manifolds (Dennis Moore wrote an article on some aftermarket ones that were cheaper than stock and performed better than stock - can't recall who made em but look up Dennis' profile and chase down that thread..)
Oil pan, Intake, Carb, distributor...

You can use your T-bolt module, alternator, raw pump, ps pump, etc...

This is getting exciting...

www.1800runsnew.com

the GM
The 350
325cshp

will need exhaust, fuel pump, oil cooler

drive now is 1.84 so that needs to be a 1.5, whats that cost to switch from 1.84 to 1.5?

props, what range should i try first?

If it were me I would leave the 1.84 and get a different prop. With that ratio if you spin a 26 pitch prop between 5000 and 5200 RPM you should be knocking on the door of 60 MPH. You are getting into a pretty big project. Are the motor mounts on the v6 the same as the v8? How about space in the engine compartment? Just throwing some questions at ya. There are a lot of horror stories out there of guys trying to get a little more and ending up not boating because of these type of problems. ;)

The boat had the option of the 5.7 back when it was built, same mounts, flywheel and the same amount of under hatch room.

You already know you need a prop.

While there are several reasons to "choose" a specific gear ratio if you are buying a lower unit, you already have one, and it is giving you no trouble.

The vertical shaft and lower gears in the drive will be subject to more torque at 1.84:1 than it would be at 1.5:1 (23% more torque). An Alpha expert would need to assist you in making the right call as far as how close to the line you are at 325hp (360 ft.lbs of torque).

If you are within the safe zone for the drive, then you can figure that @ 1.84:1 and 4900 rpm, to run 63 you will need a 28 pitch prop. At 1.5:1 and all else the same, you need a 22 or 23.

** I think you should forget about marine exhaust manifolds and just get some truck pulling headers and let them stick straight up out of the engine hatch. Your dad will love it.

ya or do it like Tim's 28 Skater with the jet boat headers. Charlie