LS Information

[72BLAZERDUDE]

Looking for a donor LS for my 72 2wd Blazer. I really have no idea what I should be looking for. 5.3,6.0,6.2 and also what transmission I should be looking for 4L60E, 4L80E , 6l80E. I have looked at quite a few adds for eng and trans complete with harness etc. I assume i want the lowest mileage i can get and I don't want a four wheel drive transmission. Is there a better year span or certain things I dont want. Price is not really a selling point if it is more complete. Lots of questions for anyone that has answers.

[mongocanfly]

to me the earlier yrs are a better choice...5.3 or 6.0, but low mileage, early yrs are hard to come by, the later yrs work, but have more of the crap on them that nobody wants
for trans a 4L60 is a 700R4 ,a 4L80 is a T400 w/od, id try to get a complete engine/trans from the same vehicle...itll make life simpler
if you want dbw be sure you get all the pedal assembly
if you have room ,it may be best to by a whole wrecked truck to harvest parts from, but no necessary,being able to hear it run before buying is a bonus
for a harness if you use a aftermarket harness ,the factory one wont matter, and ive never gotten a uncut harness with any of the engines ive bought, but i use PSI, BP is another good harness

[Willie Makeit]

very very few low mileage LS motors left out there, GM has been using the LT platform for the better part of 10 years now (2014). Summit now sells a Gen 3 450 hp 5.3 for $3,800. In my experience you'd be hard-pressed to rebuild a high mileage 5.3 that makes 450 hp for that amount.

https://www.summitracing.com/parts/s...rxcZ_eaxCKUpVr

[Accelo]

The wiring is much more complicated for the LT platform. Fuel pressure is also higher.
The transmission that correctly talks to the ECM is also limited. Even the 4l60E has an additional sensor in the pump that has to be present and connected, i.e. the pin count in the plug is different. The wiring harness is more expensive. In fact, everything costs more for the LT series.
For these reasons, I prefer the earlier motors. They are excellent motors and will run a ton of miles before requiring any machine work. Get any matching motor and transmission and go after it.

[Lokin4AReason]

i have one in my daily driver
its oke but would i put in a older model vehicle , nope
much rather the older block(s) n transmission(s)
.
ls a large amount of headaches
wiring , fuel lines , and running everything
once everything is in , sorting out the code(s) and sensor(s)
if that isnt resolved , wont run right
.
minute my vehicle is running , junking my truck

[LS short box]

So I have done both 3 and 4th gen LS swaps. Current project is a 80 Camaro with a 2012 6.2 with a 4L60E swap. Small cam headers. Runs great.
The 4th gen LS engines are 58 tooth crank gear. That means you need a ECM for engine control and a TCM for 4L60E trans control. Not really an issue. My 80 runs great.
But and there always is one I would buy a "core" gen 3 6.0 and do a mild rebuild. The 3 gen engines have a 24 tooth crank gear. That means you need one ECM for engine and trans control. Keep the original heads or upgrade to L92 heads. Small cam and headers and you will have an easy 400-420 rwhp that will be super easy to tune. 2800 billet stall converter. 3.73 gears.
Built 4L60E.
Aftermarket harness from one of the suppliers on this site or LS1tech.com. I like and use Speartech and Howell.

[cj847]

I think you need to be more specific on what you want. There is so much information available and so many "experts" out there that you will only get more confused.

What kind of build- ie if its a $100k truck buy an LS 3 plug and play from GM vs I want to do a junkyard swap myself.
Are you going to leave it stock or modify it?
etc, etc

For the very basic info I think you are looking for:
1) Gen3 engines are simpler.
2) Truck (iron block) engines are the most plentiful.
3) Almost anything you can imagine is available aftermarket.
4) For my money buy the engine and transmission together with harness and all accessories. Even this can be difficult as I have gotten complete units that the people pulling the engine cut the wire harness in the wrong places.

There are exceptions but generally:
2000-2002 truck engines were cable operated throttle body. Gen 3
2003-2006 are the same engine but are drive by wire. Gen 3
2007-2014? truck engines are gen 4
Gen 5 and up engines I don't know about other than I don't recommend them for old trucks.

[A1971Blazer]

I agree that the earlier LS engines are easier and simpler to swap in. I have a friend that buys wrecks and parts them out.
He had an '02 TransAm with 110K on it with the transmission, the harness, and the PCM for $2500.00
The car was hit in the rear but I was able to drive it before the pullout.

This is an early LS1, all aluminum engine with drive by cable.
At the time I didn't really have a project for it, so it sat in my shop, my shed, my garage, and in my way for about 5 years.

I finally found the truck I wanted to swap it into.
It became a total restoration of a '67 step side C10, so I fitted it into the bare chassis, wired it up, primed the oil pump and fired it right up.
Four years later it's on the road and running like champ.

I left the engine stock with a little tuning, and had a guy beef up the 4L60E for me, that basically all I did to it.
I also added AC and cruise control

[Jason Banks]

72BlazerDude

Check out City Motor Supply in Dallas, they have a "performance" engine you can walk in and pick up...

https://www.citymotorsupply.com/feat...s-performance/


Very similar to the Summit Reman engine posted above. With I think only rocker arms missing, if you get their shortblock and 243 heads and pay core charges it is about $1000 less. They will let you make some choices and customize.

I do think it would be an advantage to get a complete swap package from a junkyard to use for cores and you will get all the misc covers sensors and small parts. High mileage and clapped out would be just fine.

Get this book and use it as a checklist for disassembly and reassembly, even though you are not doing a full rebuild - https://www.amazon.com/gp/product/193249460X

[Lokin4AReason]

https://www.autozone.com/searchresult?searchText=engine

[LS short box]

One thing to consider on a gen3 LS1/LS6 alum block they can't be bored much due to the thin cylinder wall liners.
Iron block gen 3's can be bored .030 over no problem. Boring and stroking a 5.3 to 383 cubes has become popular.
Man I like spending other peoples money! LOL.
I have a 2002 LS6/4L60E combo in my 98 Wrangler for over 15 years. It's been a totally reliable swap and a to blast drive. Plows snow great.

[bigmoe]

Went 5.3 Gen IV with mine simply because I found a low mileage unit. Couple of small things that are better than Gen III - ECU is smaller, looks better, takes less room. Fuel system is returnless. ECU will display gear you're in if you go Dakota Digital. I think the system shows more parameters and is more tuneable if needed. You also don't need a double brake light switch.