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Ls3 6.2

J

Jswinson

Member
Hey guys what’s up I’m wanting to put a ls3 6.2l on my airboat I currently have a 13.6 by 7.6 aluminum hull setup with a 383 sbc with a 2.37 rotator. What all consists of changing from a sbc to a ls an I’m wanting to go fuel injected so can I keep all my gauges I have with my wiring harness an would it work? I’m new to the ls so any info would help?
 
The gauge panel and boat harness will work. You will have to buy an LS3 harness and ECM for the LS. That harness plugs into the engine and then you give it power and ground in a few places and your off to the races. As for the gear box I am not 100% sure but I think it will bolt to the LS3. I believe they are interchangeable. I think that you have to buy the Johnny Winters flywheel for it to work but not sure. I bought a junk yard L92 which is an all aluminum 6.2 with variable valve timing. I don't recommend doing this. I had a hell of a time finding an ECU that would run it. I did install the LS3 fuel injection and manifold on it which made it even harder to get working right. Now I will admit I am pretty new to the car motor gang. There is a lot of knowledge on this sight. Somebody will chime in with the right answers for you.
 
SBC to LS motor mount adapters.
Flexplate adapter ls crank is .400" shorter than SBC. Better to get the JW wheel otherwise you have to drill out 3 of the stock flexplate holes.
I run a holley set-up so I am not sure about the stock ecm and harness. harness hooks to all the stock type sensors oil Pressure, Water temp.
I added a oil pressure sensor and water temp sensor for my old gauges. but have the holley 3.5" screen setup which displays all the stock sensor info including fuel pressure.
There are a few good sites that explain what to remove and how to make it a 4 wire hook-up
 
Go to YouTube and type in "junkyard holley terminator x" first post should be by sloppy mechanics. It's a little over 18 minutes long and shows step by step how to take a stock motor in truck and plug in the holley efi to start.

I personally wouldn't spend money making an already efi engine into carbureted
 
I ran a carbed 6.0 the was tuned very well. I swapped to a TBSS intake 36lbs injector.
Carbed I turned 5150 set at 14.8 degrees. with the EFI I turned 5550 at 14.8 degrees now set at 15.6 I an turning 5400.

I was an Old school carb guy but this swap has made an EFI believer out of me. My system is still learning and gas milage is current a little less then my carb set-up. I expect that to change.

The other day put a fuel pressure sensor on it Boat hasn't run in 2 months hit the starter and it fired right up and idled perfect my carb would never do that after sitting for 2 months. I also run an ASA cam which can be hard to tune in a car as I understand but my boat idle at 700 perfectly. no issue at all.

I will say that was a bit of work involved my swap, but I am very happy with the results.
 
Yes I’m in Florida that’s very good info I’m hoping to get something like that I’m new to this so all this is new to me an I’m also a carb guy but like the efi better
 
So when I go to purchase a junkyard 6.2l should I get the included wiring harness an ecu or do I have to get a new one when goin efi
 
That's entirely subjective. If you plan on keeping it stock you can pull most of the parts required to run and just use them as is. It will not be pretty.

There are a plethora of aftermarket standalone efi systems. I'm personally a fan of holleys terminator kits which for 999.99 are a solid bargain. You get a new harness, ecu, wideband o2 and 3.5" display. The ecu isn't potted so you will need to install it somewhere out of the elements.

Just keep in mind there are multiple versions of the 6.2, most of which you won't find in junk yards. 6.0's are rare in them much less it's big brother.

Most standalone efi kits do not control dod or afm. So these will need to be disabled if going standalone.

Hope this helps
 
I bought the harness and ecm with the engine. Then I sent the ecm to LT1swap.com. he programmed it to run just the engine and got rid of what I didn't need. The harness I sent to another guy to break down and rebuild to run just the engine. I recommend the ECM route but if I had it to do again I would have bought an aftermarket harness. They are about 500.00 and are way smaller with new connectors. Just easier to deal with all together. Now if you get a Holley setup you can do some tuning yourself which can be both good and bad. There are also several LS3 engine builders in FL. that will build you a 550HP engine complete with injection, ecm, and harness for around 10 to 13 grand. You can go the junkyard route for about 5 to 8 grand. However from what I am hearing the valve train is week on the airboat engines because we operate them at sustained higher rpms and fails often. Mine is running great but I think I am on borrowed time.
 
Forged pistons and stronger valve springs. The hyper pistons suck for boat use and the factory springs don't like spinning 3k rpms all day. You will be under geared at stock displacement so getting a stroked rotating assembly would be a good idea as well. The Holly or mefi ecu can be tuned pretty easy by a pro for minimal cost. The stock stuff is fly by wire and I like a cable throttle.... Water thunder or turnkey build nice ones at a fair price
 
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