engine upgrades

cantboatiniraq · Sep 27, 2008

I am currently in iraq and when I get home i plan to upgrade my stock 260hp 5.7. I read that the A 1 outdrive is rated to 300 hp and that is what i have. Is there anything that i can do to the outdrive,such as change gear rings and shafts to make it more tolerable for more power.

What would I have to do to change to bravo outdrive because i know the transom mounts are different.

Bondo · Sep 27, 2008

Re: engine upgrades

What would I have to do to change to bravo outdrive because i know the transom mounts are different.

Ayuh,....

Basically from the rear motor mounts Back,....
And,...
The front of the motor will be dressed differently,... You need to install a raw water pump....

TilliamWe · Sep 27, 2008

Re: engine upgrades

You would have to replace everything from the inner transom plate back to change to a Bravo.

What year is your boat and drive? When they say 300hp in an Alpha One Gen 2, they mean 300hp at the propshaft. You'll have a hard time upgrading your 260hp 5.7 to over 300hp. And even then, if you don't hammer the throttle from a dead standstill or launch the boat out of the water off waves, a stock Alpha One Gen 2 will handle more than 300hp. Low end torque and over revving when jumping waves is what "breaks" outdrives.

Be safe over there in Iraq, okay? Thanks for the service!

cantboatiniraq · Sep 27, 2008

Re: engine upgrades

The powerhouse is a 1992. All stock. Would it help to change the shafts and gearing?
Thanks for the help. John

HT32BSX115 · Sep 27, 2008

Re: engine upgrades

cantboatiniraq said:
I am currently in iraq and when I get home i plan to upgrade my stock 260hp 5.7. I read that the A 1 outdrive is rated to 300 hp and that is what i have. Is there anything that i can do to the outdrive,such as change gear rings and shafts to make it more tolerable for more power.

What would I have to do to change to bravo outdrive because i know the transom mounts are different.

You CAN boat in Iraq can't you?.....The Tigris and the Eu should be deep enough in places

..........maybe a jet boat would be better

.... probably should have a gun on it though and maybe friendly ID so the good guys don't shoot at you!

My favorite place......(I particularly liked Kirkuk.....I think I'll get a condo over there!!!)

Your best bet would be to switch to a Bravo if you even think you'll put some serious HP in it. They're good up to about 400hp or so.... MC did put a 454 in front of the Alpha back in the 80's for a fairly short time.....Then the Bravo was introduced.

Cheers (and stay away from those IEDs!!)

Rick

cantboatiniraq · Sep 27, 2008

Re: engine upgrades

My chain if command wont let me buy a boat with gvt money. as if we dont waste enought already

Saddam lake would be a prime spot as well. I personally like the Zakho area: the judy mountains are pretty in the spring.

Thanks for the info. Im planning on pushing around 380 to 400 at the crank

jaxnjil · Sep 27, 2008

Re: engine upgrades

they make a heavy duty gear set for the 454 in 1.32:1 and 1.50:1 ratios if this helps

TilliamWe · Sep 27, 2008

Re: engine upgrades

jaxnjil said:
they make a heavy duty gear set for the 454 in 1.32:1 and 1.50:1 ratios if this helps

That would be the way to go, then.

But remember, you can't build a boat engine like you would a car engine. What I mean is, if you get too high of overlap on your camshaft, you'll have water reversion problems. And for outdrive longevity, keeping the WOT ROMS under 5500 is definately a good idea. Even Mercruiser builds their high HP engines to only turn about 5200 max. Must be a reason for it. Please, please don't apply drag race motor building rules to your boat engine. you'll be very very disappointed with the results.

chiefalen · Sep 28, 2008

Re: engine upgrades

This is big, big money your talking about. Your better off getting a boat with what you want already in it.

Boats are going dirt cheap right now with the economy the way it is.

180shabah · Sep 29, 2008

Re: engine upgrades

I don't think the 1.32:1 gearset is even available for a Gen2 drive.

If you are really in love with this boat, then swap out for a Bravo, otherwise start shopping for a different boat with more power.

jaxnjil · Sep 29, 2008

Re: engine upgrades

i didnt notice it was a II. i'm used to A I's do thay even make any heavy duty gears for the AII'S?

HT32BSX115 · Sep 29, 2008

Re: engine upgrades

cantboatiniraq said:
I am currently in iraq and when I get home i plan to upgrade my stock 260hp 5.7. I read that the A 1 outdrive is rated to 300 hp and that is what i have. Is there anything that i can do to the outdrive,such as change gear rings and shafts to make it more tolerable for more power.

What would I have to do to change to bravo outdrive because i know the transom mounts are different.

Um...Looks like he said it is an A1

I think he best bet is to go to a Bravo or keep the power at 300 or less....

cantboatiniraq · Nov 6, 2008

Re: engine upgrades

I recently found and purchased a Bravo 1 outdrive(just the drive). Are there any parts that crossover from alpha to bravo? and What all other parts do i need to finish the change?

180shabah · Nov 6, 2008

Re: engine upgrades

Trim cylinders and propeller....

You will need the transom shield, gimble housing, etc. Also you will require an engine mounted sea water pump.

Good news though - the cutout in the transom is identicle between the genII alphas and the bravo drives. If you have an older alpha you will need to drill two additional bolt holes.

bomar76 · Nov 6, 2008

Re: engine upgrades

We spent 1/2 the summer putting 450+HP (475 lbs torque) through our Alpha Gen II.. courtesy of our new 385 stroker son and I built up.
Of course we drive the Baja with some sense, never hammer it out of the hole, and avoid catching big air (have become quick on the throttle when we do

). We do run it pretty darn hard.
At winter lay up the drive oil (Mobile 1) still looked great, no shavings, etc.
We are also running a drive shower.

You can run a lot of power through an Alpha, just have to use some sense and realize it won't last forever.
Gen II replacements are pretty darn cheap, so when it eventually grenades, no big deal.

cantboatiniraq · Dec 9, 2008

Re: engine upgrades

I have recently found out that i have the vortec style(center bolt valve cover) heads. How big of a lift are those heads/springs able to handle. i want to get a new camshaft,but dont want to over do my springs...or maybe just replace them when i have the motor apart.

Big Boat Bay Buster · Dec 9, 2008

Re: engine upgrades

Good question. The actual GM vortex heads were limited on the amount of valve lift. Even though they are great flowing heads, I heard they are prone to cracks. Do you have vortex heads?--find out. Great alternative is an aftermarket vortex,check out summit for some great deals. I would take your head casting numbers and Goggle it. It would be a good idea to search the Chevy performance forums.
Chris

180shabah · Dec 9, 2008

Re: engine upgrades

centerbolt covers does not = vortec. count the mounting bolts. If there are 8(4 per side) then they are vortec heads, if there are 12 bolts then no vortec. I am not possitive about the lift limits, but IIRC it is only .478. However, they can be machined to allow different springs and thus higher lift.

BUT

This is a marine engine, you DO NOT want a wild cam, it will suck water back into cylinders - not good.

If you must upgrade the cam you best source of info will be the cam manufacturer.

Bondo · Dec 9, 2008

Re: engine upgrades

The powerhouse is a 1992. I have recently found out that i have the vortec style(center bolt valve cover) heads. How big of a lift are those heads/springs able to handle.

Ayuh,....

1992 center bolt cover heads are known as Fuelies,... Not Vortec...

The Vortec head design was intro'ed in 1996....
The Vortec head call be ID'ed by the Intake Bolts...
Vortec's have only 4 bolts on each side,...
Pre-Vortec heads have 6 bolts on each side of the Intake manifold....

Stock Vortec heads are limited to about .480 lift, before coil bind becomes an Issue...

John_S · Dec 9, 2008

Re: engine upgrades

Center bolt style valve covers would have been stock on your '92, but doesn't mean you have vortec heads. Easiest way to determine if you have vortecs, is to count the intake manifold mounting bolts. If you have 12 (6 per side) you have the standard heads. If you have 8 (4 per side) you have vortec.

PS: OK, I won the slowest typer award!

engine upgrades

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