boat newbie needs motor help

[biggboy35]

ok i have a 1989 23 ft centry cuddy with bad motor i/o 5.7 mercruiser looking to replace. is there room for up grades . the 5.7 puts out about 200 hp and was warn out being a 89 have been online looking for replacements one i have been looking is a 383 stroker that puts out 400 hp. is that to much for my outdrive to handel price for motor is like 2600 . want new life in a great boat any help plzzz.

 

[jerryjerry05]

Re: boat newbie needs motor help

You have an Alpha drive.Not really made to handle 400hp.
You'll need to beef up the lower by changing to a Bravo drive.Then the transom etc.$$$$
If you really LOVE the boat repower with a new Bravo/bigblock set up.
The sell short blocks from the GM dealers not that expensive just need the motor marinized.Unless you have FWC.J

 

[NHGuy]

Re: boat newbie needs motor help

There are lots of 383's running alpha drives. Main issue is don't do a lot of full power hole shot takeoffs. The exhaust Y pipe outlet isn't that big & will stifle some of the stroker's breathing so you'll want through hull exhaust too.
If that's just "not right" for your style of boat or boating you could go for a 5.7 Vortec motor which will do about 300 horsepower and will live right where the original motor was without issue. BTW if you have a 4 barrel Rochester your motor was probably a 260 horse, rated at crankshaft. Effectively about 230 at the propshaft.

 

[biggboy35]

Re: boat newbie needs motor help

Yes I do have through hull exhaust , and I have looked at the 5.7/ 350 , @ 300 hp and a 350 hp from us motors Inc 2200 / 300 hp , 2400 / 350 hp and 2600 for the 383 striker @ 400 hp / but long run don't want to replace drive and transome $$$$ .

 

[Fishermark]

Re: boat newbie needs motor help

Is this the company you are talking about? Marine Engines

Like mentioned above, even a good fresh basic 350 will help if your old one was worn out. I personally would just go with a crate engine from Pace Chevy or some place similar. Then bolt all your marine externals back on from your original engine.

But again , as mentioned above, your alpha should be able to handle a 383 as long as you take it easy with your right hand from the hole shot.

 

[biggboy35]

Re: boat newbie needs motor help

I have a boat repare guy that told me today that he has a new gem alpha that might fit , do you think that would help ?

 

[Fishermark]

Re: boat newbie needs motor help

Is there anything wrong with your current outdrive?

 

[biggboy35]

Re: boat newbie needs motor help

No that I know but I ment to say was a new gen alpha that is a little better than the old one that might hold up to the more hp that I am looking for

 

[Bondo]

Re: boat newbie needs motor help

No that I know but I ment to say was a new gen alpha that is a little better than the old one that might hold up to the more hp that I am looking for

Ayuh,... Updatin' an Alpha from Alpha 1, to Alpha 1, Gen.II is mostly a change in the shifting system/ linkages, 'n redesigned waterpumps....
No real efforts or changes in the structual intergerty of the drive,...

Still rated at 300hp, as it pretty much has been since the old Model 1 drives of the late 70s...

The Biggest Difference in choosing a transom assembley/ drive Alpha 1, Vs. Gen.II is the point in which All of the Alpha sieries interchange, Easily, with each other...

Basically, it's Everything up to 91 interchanges with each of the various names it carried over the years...
After 91,... Your choice of replacement/ repairs is the Gen.IIs only....

Either Way,....
Slap a Fire-breathin' 383 in there, 'n Go Boatin'.....

Either of the Alphas can be replaced at under $1500. a Pop.... Who Cares,...
They're replaced, Cheaper than can be repaired....

 

[biggboy35]

Re: boat newbie needs motor help

Ok and thank you for all your input it really helps alot , I think I am just going to rebuild my old 5.7 and change a few things , like cam heads intake and carbs my boss just told me he has a pair of built Vortec heads and and brand new cam, intake sitting . So going over tomorrow to check it out

 

[jerryjerry05]

Re: boat newbie needs motor help

They have gearing for the bigblocks that you can put in your alpha drive.It's a 1:32 gear ratio.It can handle the take off a little better.A customer I had had a Donzi with a pair of BB and alpha drives and the 1-32.
They would last a while and then something would let go.He kept me busy for a while.
He ended up repowering with Bravos.Afte that not one problem.J

 

[biggboy35]

Re: boat newbie needs motor help

ok went to boss's house he had som great stuff , 2 comptetly rebuilt vortec heads in boxes with covers , Edelbrock 7116 - Edelbrock Performer RPM Vortec Intake Manifold , Camshaft, Hydraulic Flat Tappet, Advertised Duration 274/274, Lift .490/.490 , Fel-Pro QKS2600 - Fel-Pro Gasket Kit Sets, COMP Cams 7812-16 - COMP Cams High Energy Pushrods, ARP High Performance Series Cylinder Head Bolt Kits
, Scorpion Performance 1.6 SBC Self Aligning Roller Rocker Arm , Speedway S/B Chevy Standard Premium Gear Drive part# 78400 and all for 800 bucks everything new in boxes ect heads