Can i upgrade the engine from v6 to v8

dlogvine

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I am restoring 1993 Larson 210SEI and the running parts are completely rebuil, engine rebored, serviced, outdrive serviced, impeller changed, gaskets replaced. But to my horror when I lokked at the deck under he carpet, it is deteriorated so badly that I will have to replace all the stringers and most likely the transom. I just found another Larson boat 2000 SEI 176, without the engine and outdrive. The original engine in this boat is 4.3 v6. So I wonder if I can swap he engine from my old boat 5.0L v8 mercruiser into a newer boat. My question is if this swap would be safe and not ruin he transom of the newer boat?
 

alldodge

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Going from a 21 to 17 footer and a V6 to a V8. Being the 5.0 is not much more HP then a V6 I don't see the issue. Suggest asking your Insurance company if they would be OK for anything other

Now if you were going to a 5.7 this would be ever more HP
 

chevymaher

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It would be fine. Front motor mount position is all that has to change. The rest is a direct bolt in.
 

dlogvine

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Going from a 21 to 17 footer and a V6 to a V8. Being the 5.0 is not much more HP then a V6 I don't see the issue. Suggest asking your Insurance company if they would be OK for anything other

Now if you were going to a 5.7 this would be ever more HP

I have only 5.0 from my old larson boat so what i got is what ill put in. The only concern I have now since the engine will fit fine if the wiring harness for 2000 engine is the same as for 1993. As for the motor mounts, v8 does not have a front mount, it has only a rear mount, 2 bolts through the flywheel housing and 2 side mounts, 2 bolts each, 4 alltogether. The only Mercruiser i saw with the front mount was 3.0l engine
 

alldodge

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And another question, I never puchased a hull without an engine and the outdrive. Is there any place I could check up the approximate prices? The boat hull is posted here
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/352390311723

Have no clue to advise, but my thought is the only reason to remove motor and drive is the boat was stolen, or there is a problem with the hull. Make sure to check integrity of the hull, look for soft spots.

so far as price, I once paid almost double for a piece of land because it was across from me. It was worth it to me to keep others from building, but would not be worth that much to another "probably"
 

mickyryan

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price is up to you really, it might have been a donor boat that he wanted the engine from so ask :0
 

dlogvine

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This is a donor boat, but it is sold through the auction from charity. So cant ask how much they want, it is up to the highest bidder. From the pictures of the listing, looks like the boat is in a good shape.
 

JASinIL2006

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I have a Larson 186 SEI that was repowered with a 350 Mag Alpha One Gen 2 (I think it was originally powered with a Volvo Penta 4.3L before I got it.) That 176 will easily handle a 5.0L engine.

The 'front motor mounts' that chevymaher refers to are (I think) what you are calling "side mounts"; on a V8, there are the transom mounts (rear mounts) and the front mounts (which are on the side) and are usually fiberglassed to the stringers. I believe chevymaher is correct that the front mounts for the SBC are located in different spot than those for the 4.3L. My buddy has a 4.3L and his front mounts look to be about 3-4" closer to the transom that are the mounts for my V8 (I believe the blocks for the 5.0/5.7/350 Mag are all the same). I don't know if the 176 had a V8 as an option when it was new, but if it did, the mounts may already be set to receive a V8 and installing the 5.0 would simply be a matter of drilling new holes for the front mounts (and filling the old ones).

I like your idea of using the 176 as a recipient of your engine/drive. Being a 2000, the Larson would not have wood stringers, so your chances of getting a boat with rot are much less. I don't know if they were still using a wood transom core in 2000, so check that very carefully, especially around the keyhole and the ladder thru-bolts (the latter are notorious in Larsons for leaking and causing the transom to rot). I'd bring a screwdriver and try to turn the ladder screws. If they are loose, look carefully for rot.

I don't know if a new harness would be required when dropping in a 5.0; mine looks like there was quite a bit of new wiring from when the motors were switched. That's a question for some of the others here to answer.

Good luck, looks like an interesting project.
 

dlogvine

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Thank you JAS, I will have to look at my other boat to see if the side/front mounts are located in the same place, since v6 and v8 are essentially the same engine block with v6 having two cylinders chopped. Ill definitely look for any signs or rot around the transom and ladder mount. From the pictures of the boat, looks like there is no rot around the transome hole, but id have to take a closer look once i get this boat (it is still in the auction on ebay for another 8 days)
 

AShipShow

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As long as they are both alpha 1 gen 2 boats and similar years, the harness should be the same... the only thing you might run into is the 4.3 might have had an electric fuel pump and the 5.0 should have a block mounted fuel pump so there will be some "extra wires" when you put the 5.0 in. Also, one might have an electric choke vs manual choke... so little things like that, but the important stuff should all be the same. Nothing you cant overcome.
 
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