18 Classic engine/drive/prop questions.

[Bacuda]

just bought a 94 classic 18 foot with a 350/260 horse with a cracked block.I was told it does 60. Since I'm going to redo the short block anyway, looking for a way to increased top end to about 70 miles an hour. looking for suggestions. Thanks

[pipnit]

What drive do you have?

Build a 383 striker motor maybe

[Bacuda]

Outdrive is history. Checked out Stoker. 325 plus horse.. Bravo outdrive I would guess. What parts from stock setup can l use ?

[Pat McPherson]

If she had/has an Alpha drive, buy a new SEI replacement. Changing to a Bravo requires a new transom assembly along with the drive and will cost you 4X more. An Alpha will hold up fine behind 325-350HP engine on a 18' boat.

[patricke]

+1

I just replaced my cracked block 350 mag with a brand new 383 stroker mated to my Alpha and have been very pleased. Granted, I dont have more than 10 hrs on the set up, Most people I have consulted agree that you will be fine....IF you dont get too crazy with hole shots and wave jumping.

I figured if I ever toast mine I could throw 3 or 4 more Alphas on in my lifetime for the same cost of converting to the Bravo. Not to mention significant weight difference. In addition, you can alway upgrade your Alpha with HD gears I believe.

Just my $0.02 good luck!

Patrick

[joseph m. hahnl]

just bought a 94 classic 18 foot with a 350/260 horse with a cracked block.I was told it does 60. Since I'm going to redo the short block anyway, looking for a way to increased top end to about 70 miles an hour. looking for suggestions. ThanksYou should build the short block for todays crappy fuel. Go with all forged internals ,crank ,rods and pistons. "Long rod, big bore and stroke";)

[biggiefl]

if the block is cracked you can't redo the short block anyways. You can buy a nice 400hp 383 for decent money and I second the alpha drive. Ran a 400+ 454 with one for 10 years with no problems.

[Blind Horse]

I am in the process of replacing my 350 mpi mag with a 383 stroker scorpion 400hp in a 2001 classic 18. Keeping the alpha drive. You can see some feedback I recieved in my recent thread called "Will the 383 Scorpion fit in a 1993 Donzi?" The thread started out with my inquiry about intalling my motor in a 1994 classic 18 but I ended up buying a 2001 classic 18 for the motor.

I have recently learned that the alpha drive will not supply a 383 with enough cooling water and you need to install an auxillary water pickup. After extensive research, I bought a Stainless Marine brand pickup which will require some fine tuning to get the proper water pressure to the bravo pump on the 383. At the end of the recent thread called Sea Strainers, you will find great info on the water pickup.

I am being told that a drive shower is really important and I intend to put one on the alpha and change the drive gear oil frequently.

Jeff Vander Yacht
2001 Classic 18

[biggiefl]

huh? My Alpha supplied plenty of water to BBC. How can a SBC need more?

[joseph m. hahnl]

huh? My Alpha supplied plenty of water to BBC. How can a SBC need more? It's a Bravo motor with an Alpha One drive:propeller: Needs lots of water for the water pump and all the coolers in it.


His intent was to buy a short block and use the top end and all the accessories from the 350.

[patricke]

I had the same issue with the alpha not pumping enough water to the engine. The mechanic that installed the motor saw this immediately and put in a nice ss transom pick up for me. Albeit he left it too long and the length caused unwanted trim and drag, I have since cut it down and it is perfect.

The water that is being taken in from your outdrive can simply be rerouted to dump it back over your outdrive for your drive shower :clap:....Its a beautiful thing.

You will need to keep that water flow in tact anyway I understand as it is supposed to cool some internal lower parts of your drive as well and should not be abandoned.

[Bacuda]

Joseph ...you are correct on my intent. Safe to say that I can use existing. Great info. Alpha drive ....ok tx. No clue on gearing. Would like min 70. Any special gearing. Looking for a mechanic to do the work but im a neophite when it comes to engine and drives. Want to be able to tell him what im looking for or at least have a better understanding of which set up will produce intended result.

[joseph m. hahnl]

Joseph ...you are correct on my intent. Safe to say that I can use existing. Great info. Alpha drive ....ok tx. No clue on gearing. Would like min 70. Any special gearing. Looking for a mechanic to do the work but im a neophite when it comes to engine and drives. Want to be able to tell him what im looking for or at least have a better understanding of which set up will produce intended result. There is a 1 :1.3 heavy duty gear set for high torque motors. The heavy duty doesn't necessarily mean the material is stronger or different. It usually is referring to the gears being closer in diameter to each other making the prop gear larger and stronger:crossfing:.

:eek:Important Note: Alpha Gen II drives will NOT fit an older Alpha One Gimbal.
Also the reverse holds true. The Alpha One drive will not fit the newer
style Alpha Gen II gimbal.
Alpha Ones and Alpha Gen II's are not interchangeable in any way.
Most of the parts and dimensions are not the same.
Most parts will not interchange.

You will not be able to just throw gears in it with out the proper tools .There are shims and a shim kit tool, to set a specific running torque on the drive and prop shaft. Because they are tapered gears "differential gears" running face to face, there is no method of measuring the interference fit of the gears other than resistance. " Amount of gear binding". This will absolutely determine the life of the drive. I believe that SEI "after market drive" does not make the 1 : 1.3

The 1 : 1.47 will work fine it just needs a little more finesse on the throttle:drive:

[gellis11]

Have you looked into an Alpha SS?

[MOP]

Alpha SS is nothing more than shortened Alpha 1, it is more vulnerable to air time damage. No question it will provide a decent jump in top speed but needs to be babied a bit.