Finally Started the LS Swap
 

I have been researching and wanting to do the LS swap in a boat for a long time now, and as of this morning, the old SBC 350 has been pulled from my powerquest 230 conquest and the swap has started! The new motor is a fresh 5.3L with an LS9 cam and summit aluminum roller rockers. Im going to leave it fuel injected and hopefully find a way to get o2 sensors mounted in crusader manifolds. I have lots of stuff to figure out yet but the hope is to have it running by memorial day...

https://cimg9.ibsrv.net/gimg/www.off...6345166519.jpg
https://cimg1.ibsrv.net/gimg/www.off...11fed40f6c.jpg
https://cimg8.ibsrv.net/gimg/www.off...366ca0940a.jpg

Look forward to seeing the progress

Cool project.
230 Conquest is a neat boat.

Should be a fun project! There's a dude on YouTube who LS swapped a formula 242. Not sure if there is anything useful for you but here's the link to the channel

Those are great boats that handle the water great for their size, I grew up with an 89’ 230 conquest. My dad bought it brand new, we got to take the tour of the plant.....not big, but very cool. Good luck on the swap. I hope to see ya out there this year, we are just up the big pond in GH.

Got the motor set in place today so I can start figuring out motor mounts. For some reason I thought the mercruiser flywheel would bolt up but that was not the case, im researching now what the best solution here is going to be. The mercruiser bellhousing did bolt up nicely with the exception of the top bolt on the LS block.

https://cimg2.ibsrv.net/gimg/www.off...dc2d265e77.jpg
https://cimg3.ibsrv.net/gimg/www.off...bf86d09324.jpg
https://cimg4.ibsrv.net/gimg/www.off...99a2c001ed.jpg
https://cimg5.ibsrv.net/gimg/www.off...3d35ba477e.jpg
https://cimg0.ibsrv.net/gimg/www.off...35f9bbfaba.jpg
https://cimg1.ibsrv.net/gimg/www.off...8aacae608d.jpg

Saw o2 spacers/adapters other dsy on ebay for your exhaust. Lots of $$$$. Like $500 or more.

I know torque convertors need spacer when putting TH350 behind a LS, may be similar with your flywheel issue
I would have thought spacer between manifold and riser would be cheap way to get O2 sensor in there, didn't realize $500
Have seen some home brewed ones if mill and right tap is available

Looks like im going to have to get an LS flywheel and the mercruiser engine coupler will bolt to that. Summit has a flywheel for about $120 that im going to order. I saw those spacers for the o2 sensors on ebay, but im not willing to pay that much for them. Im hoping to get the riser's tapped, or possibly run open loop.

he said putting them in header is that the best place for them ?

I got the intake manifold, fuel rails, and water pump all on. I also started on getting the wire harness installed. Next on the list is to get the fuel system figured out. My initial plan was to mount an AEM pump i have inside the tank via the sending unit hole. Then from the pump to a fuel water separator, to another filter, then to the fuel rails. From the fuel rails ill run a return line to a pressure regulator, and then back to the tank. Luck would have it though that the hole in the tank for the sending unit is not big enough for the AEM pump. So I need to either come up with a way to enlarge to sending unit hole in the tank, or bite the bullet and run an external pump.

https://cimg7.ibsrv.net/gimg/www.off...76ec016c68.jpg

ive seen some retrofit kits to install pumps into a tank that never had one fr EFI.....i just dont think an in-tank pump is "legal" in a boat. the whole design of the fuel delivery system in a boat is to minimize fuel spill into the bilge are. If you notice most if not all factory electric fuel pumps are mounted on or very near the engine. And the fuel line from the pump to carb or fuel rail is a hard line. In the even a fuel line breaks with an in-tank system it will just keep dumping fuel into the boat.
I did a quick search on the net and found this excerpt:15. Fuel pumps on a marine engine must be designed to not leak fuel into the boat. Many are double diaphragm. Today most engines have electric fuel pumps. The pump must be mounted on the engine or within 12 inches of the engine. This minimizes the amount of fuel line that is under pressure. It also means that unlike newer cars the line from the tank to the engine is under negative pressure. In other words, the fuel is sucked to the pump rather than pushed to the pump. That way if there is a leak the engine just starves for fuel and stops. The fuel pump must be fire resistant.

16. Fuel lines from the pump to the carburetor must be metal or USCG Type A marine fuel hose. This hose is fire resistant. The hose from the tank to the pump can be USCG Type A or B. Type B is not fire resistant and is hard to find.

Thank you for that information, I will go with an external pump. It will end up be easier too, I just need to pick out a pump now..

Have you looked at a corvette fuel filter ? The filter has the regulator built in so you just run a line from the pump to the filter , a return line from the filter back to the tank and then one line to the fuel rail. If you are using HP tuners ( the only one I know) find a stock tune for a later model truck with a single line to copy the fuel curve after .

Curious, why not go with a 6L or 6,2L as I think the block are all LS? correct me if I'm wrong.

just my guess- cost and dealing vvt and dod. If you blow up old 5.3 you throw it in the gutter and go buy another.

He stated on another forum that a 6.0 or 6.2 may be in the long term , but for now he is running an alpha and doesn’t want to buy a bravo. (I had the same question)

Corey331 and mgdoors have very good threads on there ls installs and the issues/fixes they ran into with builds and rigging. I suggest you deep dive.

as far as fuel pumps and etc for any decent ho engine, lots of threads on normal engines. Ext coast guard approved pumps, how to rig snd make return, etc

i may have spelled those members name wrong but will be close.

I’m on the downhill side of this type of swap too.

did you upgrade the main and connecting rod bearings? The engine will be higher revving rpm for Longer than a car. Look at kings xp (what I did or clevite h)
new pistons and rings
Deleted dod and put in ls7 style lifters
trunnion upgrade
I had to get a flywheel plate and a big merc coupler and bell housing.
did the external fuel pump (aem from summit) and dbc throttle body.
raw water pump is tricky I did the marine engine depot thing with a crank mounted Johnson pump with the mounting bracket and bushing.
running closed cooling like crusader set up their 6.0

Guessing you know Volvo has adopted these now.
I got a lot Of inspiration from ilmor and crusader but plenty others like Volvo running these now.. irocx said he was fixing his raw water pump with bracket.

Eventually the plan would be to put a 6.0 in here. I already had this motor from another project though and I will still be running an alpha 1 for the time being. I really wasnt even planning on doing this swap until someone made me an offer on the old SBC 350 set up.

I have read through there threads many times, they are very informative. I got a good deal on an AEM 50-1005 pump off the facebook marketplace that im going to at least use to get the boat running. Eventually I will get a USCG approved fuel pump and keep the AEM one on the boat as a spare.

I put new bearings in this motor, but they are just OEM ones . I did not build this motor with intentions of putting it in a boat, and at most this motor will be in the boat for this summer only. It is a fresh motor though and I did put summit roller rockers on it.

I will be use the water pump in the apha 1 for cooling, but thats all I really have figured out at this point. I have a bunch of ideas, just need my manifolds to get here so I can figure out plumbing.

well 1 season should be fine but that will put more wear than expected on it from what I’m told (it does make sense).
Curious how roller rockers do for you. I assume you mean roller tip rockers and not a trunnion upgrade?

Which manifolds did you order? I don’t recall seeing that. Also will you need spacers? I ordered these
https://www.hardin-marine.com/p-1045...-53-60-62.aspx

Yah that alpha will make things a little easier from raw water pickup point of view.

i like that that my manifolds are aluminum. I hate that I’ll have to mill my own spacers out of aluminum but such is life.
I ended up using ict and michiganmotorz for coil extenders and relocation brackets for my coils to go on transom.

im going bravo 3 and I ended up needing the shift bracket thing 807962a15
dont overlook your cooling system. I have a crusader RA0147048a for my heat exchanger and separate ones for my power steering and oil coolers.

good luck and will be watching.

Yes, the rockers arms are a full roller design and utilize a needle bearing. https://www.summitracing.com/parts/sum-g6980

For the manifolds I ordered the crusader/pcm ones and have plans to make custom stainless risers to mate to the merc y pipe. I have concerns that if I buy the crusader risers I wont be able to make it work with the merc y pipe. I should have enough stainless left over from other projects that im at least going to give it a try fabricating the risers. If it doesnt work I will re evaluate.

I got the fuel system mostly in place, I just need a fuel/water separator and a filter to go before the pump yet. The way I have it mounted the pump is almost level with the bottom of the fuel tank so I am hoping for no cavitation issues. The fuel pump is mostly wired as well, it is getting powered by a relay that gets triggered via a signal wire from the computer. For plumbing I have -8an from the tank to the pump, then -6an from the pump to the rail, and then the return is -8an. I was going to do the whole system in -8 but I could only get a -6 fitting to fit between the fuel rail and the alternator.
https://cimg5.ibsrv.net/gimg/www.off...424fcf9206.jpg
https://cimg5.ibsrv.net/gimg/www.off...e3e73b8e8f.jpg



I also got some SBC to LS motor mount adapter plates and they worked out great. The motor is now mounted, but I don't have the new flywheel yet so it is not aligned.


https://cimg7.ibsrv.net/gimg/www.off...cee25a20a9.jpg
https://cimg0.ibsrv.net/gimg/www.off...1745c40dcd.jpg

The AEM 380/400 (AEM 50-1005) I believe is CG approved. I bought those pumps for my EFI builds. I read some literature somewhere on the internet that they were CG approved. Also, they sell them on all the marine websites.
https://www.cpperformance.com/p-1008...fuel-pump.aspx

I have not kept up with the ls engine stuff for some time now, I was curious as to how aggressive the ls9 cam will be in that 5.3? only reason I am asking is because you are planning to run manifolds. I just hope you do not run into a reversion issue. I would also recommend getting that fuel pump higher up and not in the bottom of the bilge where it is sure to get wet.
Is that fuel pump safe to use in an enclosed bilge?

fuel pump is safe as it’s been used by many on swaps and I believe it is uscg approved as mentioned above.

Selecting a cam is tough. I was told by multiple sources not to exceed .227 on a cam. Reason being aggressive cams will cause reversion with both valves being open at BDC and creating a vacuum in turn causing reversion.

Not sure on the specs by OP but so far seems reasonable.
I used tsp’s high lift truck cam stage 2. Think my specs were 212/218. Multiple experts recommended a truck type cam so I didn’t lose torque down low where I need it but want power out on top.

I believe these are the specs for the cam. Its been over 5 years since I ordered the cam and I couldnt find my original order confirmation..
https://cimg7.ibsrv.net/gimg/www.off...b254adfe67.png

The picture is a little deceiving on the fuel pump, it's about 6" above the stringers yet. Ill be honest though I did not think of water in the bilge when I put it there so I probably will mount it higher yet. My main focus was low as possible to prevent cavitation.

I had a texas speed 224/224 cam in a 5.3 in my Jeep, that motor was a monster after 3000 rpms but definitely lacked in the low end torque

I have to ask because it’s bothering me; is that bulkhead where the pump is mounted permanent? It looks like it’s bare wood. Once the bilge gets wet in there, that panel is going to be junk in a quick amount of time.

Just an observation.

yup,,that bare plywood needs to be encapsulated in resin and fiberglass.

It is bare plywood, but its not actually the bulkhead. For whatever reason it is screwed to the bulkhead, maybe for extra support? I poked around at the actual bulk head and it all seems solid
https://cimg5.ibsrv.net/gimg/www.off...d9dc88013c.jpg

Are those drywall screws holding it on????

Yep...
This project just got a whole lot bigger..
https://cimg6.ibsrv.net/gimg/www.off...927de85697.jpg

Ooffff!!

Working with pumps for the last 21yrs i can tell ya those are roller vane impeller type pumps so the only way you will cavitate it is if you have too small of a feed line from the tank to the pump or if the gas level is low enough that you suck air into the pump.... actually there is one more thing...the check valve at the tank fitting outlet. So i wouldn't really worry about placement of the pump. Obviously if the pump is mounted at the top of the engine then it has to work harder to pull the fuel up to itself but for basic installs on a boat i wouldn't worry about it being at the very top of a stringer or even slightly higher :)

What flywheel did you use?