Installing new engine, need help, quick questions, I promise :)

J

jstcrzyengh

Seaman
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Jul 31, 2004
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Ok here is the situation. I have a 1971 IMP it has an OMC 350 that is in need of a rebuild. I just so happen to have a 355 shortblock that I built for another project. I would like to know what differences there would be. It seems to me if it all hooks up at the flywheel that this engine should just drop in with little to no problems, but I wanted to make sure. Is it just a bolt in? I will be going with Vortec heads and a demon carb. I also want to switch to closed cooling instead of raw water. Anyone know of a kit for this type of project?<br /><br />thanks in advance<br /><br />James
 
tommays

tommays

Admiral
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Jul 4, 2004
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Re: Installing new engine, need help, quick questions, I promise :)

the bigest difference in a marine engine the freeze out plugs are brass and the head gasgets are a marine grade as is the water pump<br />just remenber that any auto electric parts fuel pumps and carbs are a no go and have to be marine rated<br /><br />tommays
 
J

jstcrzyengh

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Re: Installing new engine, need help, quick questions, I promise :)

Hey Tommays. The freeze plugs are already brass (as those are un upgrade for an auto engine) and I planned on using every other part from the old engine that I could. Though I will probably have to spring for a new water pump (V -belt to serpentine) I will not use any Automotive parts other than the base engine. The engine itself is completely balanced and blueprinted and has all forged internals, so I am thinking it should be great for a boat engine. But from what you are saying it is a same for same swap?<br /><br />James
 
E

elpaso

Petty Officer 1st Class
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Jun 27, 2003
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264
Re: Installing new engine, need help, quick questions, I promise :)

Are you in fresh or saltwater ? Include all details - what year is rebuilt engine.<br /><br />Is a 1971 boat worth the trouble and expence ?<br />With an outdated OMC outdrive. That was nothing <br />much when new. Parts will be a problem.
 
J

jstcrzyengh

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Re: Installing new engine, need help, quick questions, I promise :)

Elpaso<br /><br />The boat will be in both Freshwater and Saltwater. Saltwater in the summer and fall and Freshwater the rest of the year. The rebuilt engine specs are as follows:<br /><br />1993 2 bolt 350 (bored out to 355)<br />Block deburred align honed/deck plate<br />ZZ4 crank<br />1 piece rear main seal<br />BBC oil pump and pickup<br />Moroso 6 qt pan<br />Clevite 77 bearings<br />Forged I beam rods<br />TRW forged pistons L2256<br />Moly rings<br />ARP bolts everywhere.<br />Needless to say it was built to tkae a continual beating from a super charger, and rev high so it should handle in a boat without much trouble, but again I am not the expert with boats. I also just went through and spent over $2300 into the outdrive, New magnets, new springs, new wiring, new tilt motor, so that is all new. The engine is just sitting. It had AFR heads to go along with it, but they are aluminum and though aluminum itself is ok with the salt, it being next to other metals I was told it would get eaten away very fast. I also want to convert to close cooled. <br /><br />The boat rides very well, has a great cuddy and has a lot of potential. I am looking at it as a project boat, but would take it to san clemente island out here (60 miles) with little to no problem, AFTER the engine switch. What do you think?
 
X

xltier

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May 20, 2004
Messages
636
Re: Installing new engine, need help, quick questions, I promise :)

cam shafts are different also.marine has a different duration and lift.marine engines need to develop h.p. at a lower rpm.
 
J

jstcrzyengh

Seaman
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Messages
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Re: Installing new engine, need help, quick questions, I promise :)

Right. I know you have to use a mild RV cam to make the torque way down low to get the boat up on plane as quickly as possible. I will change over to a smaller cam, since it is a LT4 hot cam in there right now :) But as far as hooking up to the sensors and outdrive I should have no issues right?<br /><br />James
 
D

DJ

Guest
Re: Installing new engine, need help, quick questions, I promise :)

James,<br /><br />The engine swap should not be a big deal.<br /><br />However, I'll warn you, that outdrive will not take a lot of horsepower. It was marginal with what it had new.<br /><br />It will live if you don't thrash it.
 
Bondo

Bondo

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Re: Installing new engine, need help, quick questions, I promise :)

That $2300.00 you spent on the Drive, is going to sound like Loose Change..... Before you're done........<br />That Eletric Shift will Never Last......<br /><br />That sounds like a Great Engine........<br />But,<br />It's ashame to Waste it in the Wrong Application........<br />
a super charger, and rev high
Click to expand...
Super Charger ??? Doesn't that mean Low Static Compression ???????<br />High Revs ??? Your Outdrive will Come UnGlued a little over 5Grand........<br />As stated by xltier, You'd Better be Recamming it....... I'm Sure the Grind you have in there Now, Is Not What You Want.......<br /><br />If you Really Enjoy this boat,<br />Drop an old Junkyard motor in it,+ Go Boating...............<br />If you're just looking for a stable to park that Fire Breathing Motor,<br />Buy a boat with a Black outdrive............... ;) <br />
But as far as hooking up to the sensors and outdrive I should have no issues right?<br />
Click to expand...
You Might have Issues with Flywheel Diameters,+ the Coupler....... Due to the 2piece, Vs. 1 piece, rear main seals.....
 
D

DJ

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Re: Installing new engine, need help, quick questions, I promise :)

Hey Bondo, Even an Alpha I (black drive) struggles with a hopped up 350. ;)
 
Bondo

Bondo

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Re: Installing new engine, need help, quick questions, I promise :)

True Enough.......<br />300 Max... for reliabiliy.......<br /><br />But,<br />The Bravos will take it......<br />And,<br />Aftermarket Parts will get it to the 1000hp range......
 
D

DJ

Guest
Re: Installing new engine, need help, quick questions, I promise :)

Agreed, The Bravo is a a beast.
 
J

jstcrzyengh

Seaman
Joined
Jul 31, 2004
Messages
55
Re: Installing new engine, need help, quick questions, I promise :)

Well, I am looking at a HR-260 from Crane Cams. Unless someone has better advice for a cam? I am either going with L98 or Vortec heads. So I will probably, especially with that cam, be putting out what the factory set it as 245hp. MAYBE if I do some home porting to the L98 heads I can get 260, but that cam wont pull as much air as those heads produce stock. With a 600 - 650 carb. I would rather have the Bravo drive, as that is what I am use to, but the cost to switch out is way too much. Also I have no other place for this short block so the boat is a perfect place for it :) <br /><br />Does anybody know about the issues with the coupler? The flywheel is the same, so if it hooks up to the flywheel I dont foresee me having a problem, but can anyone confirm this?
 
J

jstcrzyengh

Seaman
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Jul 31, 2004
Messages
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Re: Installing new engine, need help, quick questions, I promise :)

No one knows if the coupler will go or not?
 
B

bluewater19

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Apr 25, 2003
Messages
505
Re: Installing new engine, need help, quick questions, I promise :)

I thought L-98 heads are aluminum also? Those are the heads that come on the ZZ-4. If you use closed cooling I would stick with the AFR's. If you are going to use cast heads I would use the vortec heads. They are cast versions of the LT-1 heads and will flow better out of the box than L-98's with pocket port work.<br /><br />Good luck with you boat!!!
 
J

jstcrzyengh

Seaman
Joined
Jul 31, 2004
Messages
55
Re: Installing new engine, need help, quick questions, I promise :)

I thought L-98 heads are aluminum also? Those are the heads that come on the ZZ-4. If you use closed cooling I would stick with the AFR's. If you are going to use cast heads I would use the vortec heads. They are cast versions of the LT-1 heads and will flow better out of the box than L-98's with pocket port work.<br /><br />L98 heads are cast, you are thinking of the heads on the Vette's. All other L98 (350) were cast. ZZ-4's again are the D-port (88+) vette heads. Though I do need to tell you Vortec heads are not LT1 heads. They are completely different animals. For one the LT1's use reverse cooling. I actually looked at possibly using a Lt1 intake, but again for a boat that needs 250hp to let it do 40mph I didnt want to spend too much money. <br /><br />But one thing I noticed about the closed cooling. If I go with a closed cooling system I can than use Aluminum heads and not worry aobut electrolysis?
 
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