The long and short of LS swap

[Security guy]

I know there's a million threads on swapping an LS motor into a truck, but without reading a bunch of threads of how to do it, what is the short version? From what I know, you gotta have the motor mounts, oil pan, obviously the correct headers, transmission, etc.. The question I have is, do you need an oxygen sensor, the computer harness, the digital gauges, programming, fuel pump, etc to make it run? Would it not be more simple to put a carb on it and be done? The last time I messed with fuel injection, it was a major pain with all the electronic stuff involved just to get it to run. Have things become a little simplified from 10 years ago? And what's the over-all cost comparison? I know an LS motor could be gotten for just a little more than a traditional small block, but does all the other stuff add up to be way more than sticking in a 350? I had a 5.3 Silverado that ran awesome, but how many years of driving to get better mpg does it take to pay for the change to an ls motor? Just thinking out loud...

[hugger6933]

Ok you can stick on a carb but the intake and MSD box to make it run is gonna cost about the same or a little more than a computer reflash and a harness rework. You can do that for $3 to $400 bucks anywhere, and that is gonna be the difference. You still have to buy a pump either way and motor mounts as well. you don't HAVE to have headers but there are some in the under $200 bucks now that look pretty decent.
One BIG HUGE thing is if you co carb you gonna either have to go back with a 700 R4 or lose the overdrive altogether and that is a big benefit to going LS

[Robznob11]

Originally Posted by Security guy

I know there's a million threads on swapping an LS motor into a truck, but without reading a bunch of threads of how to do it, what is the short version? From what I know, you gotta have the motor mounts, oil pan, obviously the correct headers, transmission, etc.. The question I have is, do you need an oxygen sensor, the computer harness, the digital gauges, programming, fuel pump, etc to make it run? Would it not be more simple to put a carb on it and be done? The last time I messed with fuel injection, it was a major pain with all the electronic stuff involved just to get it to run. Have things become a little simplified from 10 years ago? And what's the over-all cost comparison? I know an LS motor could be gotten for just a little more than a traditional small block, but does all the other stuff add up to be way more than sticking in a 350? I had a 5.3 Silverado that ran awesome, but how many years of driving to get better mpg does it take to pay for the change to an ls motor? Just thinking out loud...

I bought motor/tranny/harness/computer/manifolds had the o2 sensors in them. even the tranny yoke for 1900, wired it my self using LT1swap.com directions and 40$ in parts. I Made motor mount adaptors and tranny x member for 125$ worth of steal( used clam shells and stock mmts and towers. Fuel tank is out of a 02 camaro from salvage yard 90$ pump included. 100$ more for 3/8 roll fuel line, brass fittings, fuel injection hose and parts( narrowed double flare tool from AutoZon) drive shaft was 300$ to have made but it's overkill will hold 800+ hp. Radiator was 100$ New off eBay for 02 vette , dual fans 15$ off a v6 camaro ( fit like a glove on rad) I also got the oil cooler and trans cooler lines with my package and vet radiator has built in cooler( I have since swapped to aftermarket oil cooler cause I could not stand the slight oil drip from oem fitting) 200$ for headers off eBay, 180$ summit exhaust kit, 80$ for mufflers, that's about it. I was sure to get hoses , belts, sensors you name it with package and make sure they done cut wires. By the way it fired and run with first crank( I only paid 75$ for my mail order tune at wait4me performance it's more now, but he reflashes free and after my cam swap it fired and run first try again) should I also mention I only have about 400$ in that swap as well .

[juddss]

Good Info l. I have a 13 escalade 6.0 I was going to sw as p into my 70 suburban this winter. Sucks I need a linginfelter adapter to change the crankshaft and cam reference to 24x. But it's worth it because I got the engine with 60k miles for $400

[Security guy]

Interesting... so it almost sounds like its not to big of a deal to go LS.. Where do you hide the computer and all the wiring? I've seen some pics of swaps that look terrible, then I've seen some that look awesome with little or no wiring visible. Is it a pain to wire the thing up or is there a simplified kit you can get for the basics? And does all the factory gauges work with the LS stuff?

[Robznob11]

Originally Posted by Security guy

Interesting... so it almost sounds like its not to big of a deal to go LS.. Where do you hide the computer and all the wiring? I've seen some pics of swaps that look terrible, then I've seen some that look awesome with little or no wiring visible. Is it a pain to wire the thing up or is there a simplified kit you can get for the basics? And does all the factory gauges work with the LS stuff?

I used a factory truck computer mount bolted to the core support , right above it is a repurposed msd box that hides my relays for stand alone. I'm running intellotronix gauges(digital) you can get referbs cheep off eBay . In these pics I have make shift power wires run. It's even cleaner done.

[Security guy]

That looks good... still looks like a lot of work compared to a traditional small block. The wiring part of it scares me more than anything. Not sure that's a hurdle I want to cross yet...

[Robznob11]

Originally Posted by Security guy

That looks good... still looks like a lot of work compared to a traditional small block. The wiring part of it scares me more than anything. Not sure that's a hurdle I want to cross yet...

Honestly your wires are all in the oe harness, your left with 6 wires after you rework the harness and you don't even have to use them all. Some of those looms you see are my e fan wires and relays I ran that are next to the stand alone system. It really is gravy to install.

[juddss]

Looks great! I was thinking of trying to do a wire tuck on mine when the time comes. Sheetmetal intake would make it look even better!!!

[H20cooled]

The wiring was honestly one of the easiest parts of my LS swap, I bought a good new wire harness from BP Automotive (one of the site sponsors) and it took all of 5 mins to plug it in. The just connect up the power, ground, etc.. and it was good to go. The hardest part of the swap was finding the place to put stuff and making it all look good. Its funny I always thought the all the electronics would make this so much harder that the old school SBC setup but it doesn't at all it is actually easy. Since I connected everything up and got the motor running I have not had to play with it once, I've had no leaks, running or driving issues, or anything else engine/tranny wise. The only problems I have had was related to suspension, brakes, and other truck stuff.

Rich

[hugger6933]

The plugs will only go one way, the right way . Once you start to drape the harness over the motor it is self explanatory.

[Security guy]

That's good to hear guys.. It sounds as though the aftermarket has made it 'simplified' over the years. I'll definitely consider the LS when the time comes.

[Zoomad75]

Below is a shot from my LS swap. Larry's done the lion's share of the heavy lifting, where I've done the research to lay it out for us. Larry's depth of knowledge on his 8.1 swaps for the fuel and wiring was important too. You can make it as simple or complex as you want. We wanted simple and reliable as this rig is going to take me to some remote areas you just can't walk down to the local parts store to get something for it.

So we didn't breathe on the engine to take it from stock. No big rowdy cam, no headers, nada. My research found for the 5.3 All big cams lost torque down low. Which shouldn't surprise anybody, but I want all the torque as low as I can get it as it's going to crawl. The engine control module and harness were something I traded Larry an 8.1L big block for. It's a MEFI4 Controller and custom stand-alone harness. The harness is better than factory in fit and finish. If you spend money on anything get the best harness already done you can afford. It will pay off in the end. The MEFI system is much simpler in design and does not require a MAF sensor. It's the same basic control system used in GM crate Ramjet 350's and 502's as well as what is sold with Turnkey's crates. The harness allows mounting of the ECM just about anywhere, but we are putting it under the dash using the factory hole in the firewall where the TBI harness passed through.

The fuel pump situation was easy on mine as the 91 was already running one for the TBI. We just had to drop the tank and replace it with another a/c delco unit for a L98 tune port as the MEFI runs a lower fuel pressure spec. If your truck didn't start with FI, just get a tank from a 87-91 squarebody truck and swap the pump out. We did have to address some plumbing for the higher pressure but Larry's recipe from his 8.1 swaps using a set of feed and return lines from a Workhorse RV mated right up to the stock 5.3 fuel rail.

Mounting the engine had many choices. I settled on Dirty Dingo Slider mounts. This allowed the 5.3 to set in the stock SBC location and not require major driveline modifications. This also set the 5.3 far enough back to allow the use of stock truck manifolds, in my case a set from a H2 without needing notching of the top of the frame rail. Again, keeping it stock and simple.

The install goes pretty standard, but in our case using the older 700r4 with the 5.3 creates a couple of new issues. Mating the older torque converter to the 5.3 requires using the right flexplate and spacer and some fine tuning of the holes with a die-grinder. The 700r4 requires the use of a TV cable which the 5.3's never needed with a 4l60e. Bowtie overdrives makes a great kit to make this happen. Very complete instructions and high quality parts to mate up to the 5.3's cable driven throttle body.

Cost wise, I'm probably not far off of a full blown rebuild of a standard SBC with actual $$$$ paid out. However, the engine was free to me. I've horse traded a ton and sold a bunch of stuff to offset costs.

Key tip- When sourcing the engine, get EVERYTHING. My engine was a bare long block as it came out of a customer's truck we were putting a crate engine into. So the intake, exhaust and accessory drive systems got put back on the crate. Larry and I had to dig around and find those parts to complete my engine. In some cases buying those separately can be almost as much as buying an engine. That was a PITA part of the process for me. This also included chasing after the coils and coil brackets and other little items that would have been there had I got a complete assembly. Just the coil brackets were $30 my cost through the dealer, retail for the average Joe is even more!

The harness is installed in this pic, just not routed through the hole in the firewall yet. As you can see, the MEFI4 setup makes it a very sanitary install and no spaghetti mess in sight.

[BigDan3131]

They have separate controllers for the trans if you wanted to keep the 4l60E or the 4l80E and they will provide all functions. Most are right around $500-600 for the controller or if you don't mind shifting every gear there is a black box for about $200, which is what I plan to do.

[SierraMtns]

Cool thread. Thanks for sharing guys.