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.