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Thinking of going Vortec.

topgun said:
Thanks Kurtster. I have always wanted to build a marine engine. So If I start with a fresh 30 over short block and say I throw a set of new vortex heads and intake with a mild roller cam what would the improvement be about? One other thing. Just how much power can an alpha gen 2 handle comfortably.
One more thing. What do you guys think about this whole auto engine is different from marine stuff? I know the cams are different as are the external accessories but its the internals seems that nobody can agree on. I trust the opinion of this forum better than what I have read elsewhere.
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I nice pair of V-Tx heads with the appropriate int manifold should add approx 30hp
As far as the Alpha gen2, they are a "little" tougher than the original but not by much. Theres a couple of schools of thought on this, however in simple terms both the Alphas are good for a boat that doesn't pass the 60+ mph by much.
But keep in mind that it's not so much the actual speed of travel the boat is going, it's more of how much up and down aggression is used on the throttle AND how often the prop leaves the water AND how the pilot handles the throttle in those situations.
My thought is if you have a boat with a top speed of less than 65 and a rpm red line less than approx 5500 and your HP is less than 350, then the Alpha not only is fine but in some cases preferred.{I'm sure there will be experts who don't agree with that:)}

The difference between car and marine is paramount {never ever use a car mota in a boat}.
Internally speaking the most important difference is the main bearing carrier, --marine engines use a 4 bolt main {as in a truck motor} whereas a car motor uses a 2 bolt main,-- because of the extreme low end torques needed in a boat application a 2 bolt main just don't cut it.
Also internally, the cams are designed to also accomidate the extreme low end torques in marine engines.
Valve lapping is another difference.
The external differences include {but not limited to} starter / alternator / carb / dist / etc....
 
Thanks for your input Kurtster. I think if I have the machine shop loosen up the tolerances up a hair I would be fine. As much as I tried, I can't find any good reason why a a 2 bolt won't work. I know that a boat runs at higher revs for longer periods but I doubt that a well built block would give any problem. And I would guess that not all marine engines are 4 bolt either. From what I have read so far the pro's and con's are the same kind of arguments I have been hearing in the automotive field for decades. Besides I am not building a 600 hp 8000 rpm engine. Also if the machining is going to cost more than a new block than I will just order one from summit with the 4 bolt.
 
Why mess with a donor motor from a old pickup when you have a great block already in your boat. If yours is in good condition pull it and have the machine shop give it a refresh and swap on the vortec parts you want to add. You already know what you have runs great.
 
You guys are alright. Maybe I am just being a YING YANG and should just work with what I have. I am moving my stuff to a bigger shop soon so I will have a lot more room to just throw her in a corner and get everything else that she needs done once and for all. Interior,floor,gauges, install the new steering wheel, Finish the stereo, Interior lighting, Get the windshield frame powder coated. So all this engine stuff is a while I am at it kind of thing. We'll see. I keep you guys posted.
 
Nice thing about building a seperate engine thoughis say you are working on your new mota on some random Friday night in the summer. While putting your new pistons in your freshly machined engine block, you start to uncontrolably make "vroom vroom" noises. Then as you are sliding your new lopey cam in, you catch yourself impersonating the sound your new engine is going to make at idle.....you get excited....you need a fix.... well guess what? Your boat still runs and has a complete motor in it!!! You hook to it Saturday morning and yank it to your local wet spot and have an awesome day on the water!! All because you decided to not yank your perfectly good running engine out of your boat and, how Kurster put it, "Fix something that aint broke."
 
500 hours is not a lot of hours for that engine. they go well into the thousands with proper care. just run it.

if it aint broke don't fix it. any mechanic worth his salt will tell you the same thing.

if its knockin or smoking real bad maybe look into it....but otherwise just leave it,

if you have to get a new engine then do as some others have suggested and leave the engine in your boat and use it while you scrape together the parts for you new one.

the LS swap cn be done very reasonably if you just take your time and source the stuff. and for your projected 2300 initial purchase price I think the LS would be the better choice. better engine in every way. not just horse power.
 
Still gonna build an engine but all the other cosmetic stuff is first. Right know mechanically she is perfect. Which is why I only got to really drive it only once last year before putting it away. I replace everything and fixed all that was wrong with it. The interior is the priority for now. getting the loot together to give Checkmate a call in about a month or so.
 
Wasn't really looking. But I just scored a set of really nice used vortec 062 heads for 75.00. I will just send these out to my guy for a complete once over and just put them away till the time comes. Couldn't let them get past me at that price.
 
I don't blame ya!!! That seems like one heckuva deal. Buying all this big block stuff for my build really makes me miss the days of building small blocks for my race car. Small block stuff is sooooo much cheaper!!! Kinda makes me want to try a LSX swap in my 253!!
 
topgun said:
I see an LSX swap in the cards for me to one day but not on the boat. But in my 240sx.
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Now you're talkin!!! I have very very seriously considered royally pissing off the Turbobuick crowd by LSX swapping my GN. The main thing I miss about my mustang is the v8 sound and bangin gears. So why not do that in a big comfy Buick?
 
put a vortex in a 26' SeaRay, ran great, had some carb issues, was told it is not good without closed loop cooling, evidently pockets in the casting don't drain well, it ran great until my Dumb A$$ brother let it freeze. Intake from the older will not fit, and look at the coupler, fly wheel different size. my .02
 
I put a set of Vortec heads on my 1984 SB Chevy big tire truck I built. Got them completely assembled from Summit about 10 years ago. They definitely gave me a good power jump over the stock heads. The center bolt valve covers are nice too! Just thought I'd share my personal experience with Vortec.
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