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Thinking of going Vortec.

topgun

topgun

Well-known member
Hello everyone. I have been away for awhile since I have had a lot of changes going on in my life. I hope everyone has enjoyed their Holidays. And that all of you are doing well. OK. So I for the past couple of months have been thinking of upgrading the engine in my boat. Some of you may remember my odyssey with this thing last year and that I only got to drive it only once before I put it away for the season.
Call me crazy but I have been thinking if replacing the non vortex engine in my boat with a vortec motor would be worthwhile. She runs really well but with almost 500 hours on it already I would think that a rebuild isn't to far away.
Again I have a 91 persuader with a 5.7 mercruiser alpha one gen ll. I just need to know exactly what a swap like that involves besides the intake manifold being different. And the Vortec needing a different fuel delivery….Thanks..Rich
 
How about a simple rebuild of your current 350 then bolt on a pair of higher flow rate v-tech heads and a int-manifold to match.

You said the 350 you have now runs great with about 500 hrs on it ---- that sounds like a keeper to me ---- good candidate for a rebuild, with a little added "umph"

Just my thoughts.....
 
Thanks guys. But an LSX conversion sounds like to big a project for me and expensive.
Kurtster! Wouldn't it just be more cost effective to drop a reman vortec 5.7 like from michigan motors. They sell the complete long block for about 2300.00. And I have the benefit of a roller cam and lifters. I'm thinking it might just wind up costing the same as just a rebuild with vortex heads and intake.
 
corey331 said:
Heck, in my opinion if you are going to spend the money on a complete build. Go with an LSX motor. Start with a 6.0L and build from there. You'll get a lot more bang for your buck.
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Here is everything you need to know. Not as bad as you would think.

http://www.offshoreonly.com/forums/general-q/301360-whats-truly-needed-swap-ls-engine.html

you can find running take-outs on craigslist for under a grand usually complete with harnesses and everything. Swap to a marine cam and slightly better valvetrain parts and bingo, awesomeness is achieved. Factory components can get you 400+ hp with cam and tuning change alone.

I have been researching this a bit for a possible future project. I have been wanting to build a nice LS for a while. Awesome platform.
 
Thanks for your response guys.I would like to try an ls set-up on something one day but I don't think I am ready to try that type of swap right now. So I think I am just going to go old school and build a new engine myself. Turns out today a buddy of mine let me have an 87 chevy truck motor. I could use the block since its a roller block and then put a pair of good vortec heads on it with a nice roller cam and lifters add a new intake manifold and call it a day. Not looking for the moon just around 320 hp or so. Don't want to frag the drive with to much torque.
Any advice in that direction would be very welcomed.
 
if you are staying with the std small block, hard to beat the 40+hp from the vortec heads, have done several of these, now the LS deal is great, 6.0, but is going to be more $$$$ with the manifolds, add ons, computer etc, but if you want to go that route can help you there as well...
 
Great to see you back on the forum Rich. Hope all is well and good luck with your new motor project . With only 500 hours on your small block you still have at least 3- 500 more to go . I was thinking you had an alpha and an LS would be sweet but the beginning of another project. Whatever you decide im sure it will be sweet.
 
Problem Child said:
Great to see you back on the forum Rich. Hope all is well and good luck with your new motor project . With only 500 hours on your small block you still have at least 3- 500 more to go . I was thinking you had an alpha and an LS would be sweet but the beginning of another project. Whatever you decide im sure it will be sweet.
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X2 what makes you think the motor you have is even close to done? Are you getting lots of blow by out the crank case vents? low oil pressure? wet spark plugs? Stock black Merc engines go allot longer than 500 hours(1500-2000 is very possible) if they have been looked after.
Did you buy the boat thinking the motor was finished or do you just want more power?

I'd drive it 5 more years, then think about the new motor.
 
Thanks guys for the welcome back. I am in no way saying that I think the current engine is done. Its just that after building the engine on a Vette I just acquired a few months ago I just thought that building a new motor for the boat would be fun. And with all that is going on right now I don't think I will be able to see the water this year so that has me thinking that doing the engine and the interior work would then make sense to do this year then. I can also maybe address a small soft spot on the floor while I'm at it.
I now have an 87 pre vortex truck engine that I want to build. Its the same generation as the current engine except the boat has a mechanical fuel pump and the new block is not drilled for one and it is already a roller block. Anyways I figure that if I start with a fresh short block and a roller cam and some decent heads I will be ahead of the game if I decide to make further upgrades later on. Like I said before I am not looking for a screamer just a little more than the 260 that I currently have without going overboard. I know I can have that with the engine that is in it but whats wrong with starting with a new canvas?
 
Carry on, no need to justify what you're doing to us/me. I was just a little concerned you may have thought the current motor was about to let you down.

I'm sure you know this, but you are about to "fix" something that is not "broken". There is likely to be a couple of "What the heck was I thinking" moments along the way, but what fun would it be leaving "well enough" alone.
 
karzrus said:
Carry on, no need to justify what you're doing to us/me. I was just a little concerned you may have thought the current motor was about to let you down.

I'm sure you know this, but you are about to "fix" something that is not "broken". There is likely to be a couple of "What the heck was I thinking" moments along the way, but what fun would it be leaving "well enough" alone.
Click to expand...

Yeah I know. Leaving things alone has always been a problem for me. I wouldn't be the first time I have taken a perfectly running motor out of something to replace it with something else.
 
topgun said:
I wouldn't be the first time I have taken a perfectly good running motor out of something to replace it with something else.
Click to expand...

O ya ---- been around that block {no pun intended} a few times.

All of your options are viable ways to approach it,-- as you know and has been said, --do it the way it makes you happy and the method that brings you the most enjoyment.
In the end you end up with a persuader thats already beautiful -- even better when your done--- ya can't go wrong either way.
Good luck man
 
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.
 
Inconel exhaust valves a must. Use good springs and retainers, heavier pushrods, roller rockers help but not essential depending on your goals. Valvetrain in marine engines need to be stout. Also, vlearances are different than auto because of differences in load and block temps.
 
If I were you, I would run it in the spring and see how it does. IF it is not running well, then buy a long block and go from there. I would not open up the current engine and start messing things up. We all know how that usually turns out.

Another way to look at it... You could spend 4 grand on a new engine and not gain a single MPH over what you have now.

Yet another way to look at it... If this is your dream boat and you plan to die with it, spend the funds and be happy.

Any way good luck. :cheers:
 
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