I think I just scored a good score

[mvfd70]

I just found a 4.8L out of a 2000 Chevy truck. Wasn't going to go this route but I don't think I could pass on the deal. I'll be picking it up tomorrow. It's a running engine with supposedly around 175,000 miles. They said it was running when pulled from the wrecked but driveable truck. All accessories including PCM and harness come with it. All this for a mere $100. I'll try to post pics if I end up getting it.

[dan76]

What are you going to put into? 4.8s were available with a 5-speed manual in that year group. Did you get the trans?

If you didn't get to hear/see it run, I'd pull it apart for rings/bearings while you can. Shoot some pics

[mvfd70]

I don't think the trans comes with it. I'm going to look at it tomorrow. The plan, if I end up with it, will be to put it in my 68 step side. It's not the original 250 that I had planned but this will be cooler IMO. I have a T-5 from a Camaro but I havn't decided it I want to use it or find a different trans.

I figure for a hundred bucks I can afford to do a rebuild if its needed

[dan76]

Originally Posted by mvfd70

I figure for a hundred bucks I can afford to do a rebuild if its needed

It's a good deal, I'd jump all over it if I had found it.

Does he have anymore?

[mvfd70]

Well I ended up getting the motor. Got it from the mechanic that did all the service work for the truck that ended up being the donor. As the story goes, the truck was in a wreck and was having transmission problems before that. They owner basically gave the truck to the mechanic after the wreck. Mechanic pulls the motor and scraps the rest of the truck. I did get the PCM but unfortunately they cut the wire harness in half. So I have to get a new harness or spend hours soldering that big bunch of wires back together. Here's a couple of pics.

I had to drive an hour from home and pay One bill for it. So I think I did pretty good.

Now I just have to learn all about LS engines.

[mvfd70]

Where is a good place to get a PCM harness for this thing? Junk yard or buy new?

[weircc]

junk yard but keep in mind u will most likely have to send it somewhere and get security removed pretty sure painless wiring does this cheap im sure someone else will know more

[68 IRON]

Originally Posted by weircc

junk yard but keep in mind u will most likely have to send it somewhere and get security removed pretty sure painless wiring does this cheap im sure someone else will know more

Security? Matching the PCM to the engine? Never heard of that (course I'm not a computer type guy for vehicles....tryin to get away from it)

[weircc]

no all the newer pcm's have security has nothing to do with it matching the engine even the one that came with it would need it what happens is they will start but only run for 10 min or so then it will shut off because of security

[Sport/Truck]

Originally Posted by 68 IRON

Security? Matching the PCM to the engine? Never heard of that (course I'm not a computer type guy for vehicles....tryin to get away from it)

Then you just went in the wrong direction.
s/t

[DirtyLarry]

Originally Posted by mvfd70

Where is a good place to get a PCM harness for this thing? Junk yard or buy new?

You’re better off without the donor harness as reworking a production vehicle harness into an older truck never works out right. I recommend a harness from Howell Engine Development. I have used a few of their harnesses in past projects and they are much higher quality than anything you can get from Painless Wiring. Howell can also do any special ECM tuning that needs to be done such as turning off that EGR and well as turning off torque management adding a hot tune, etc. For $100 that is a great score!

Here is the harness you need if you go the 4L60E route. It would be the best money you can spend on this project besides a thorough engine cleaning and painting. When it comes to EFI conversions the biggest mistake everybody makes is skimping on a harness and trying to reuse the OEM harness.

http://www.howellefi.com/customer/ge...nsmission.html

[usmcchevy]

Originally Posted by mvfd70

Where is a good place to get a PCM harness for this thing? Junk yard or buy new?

car-part.com you can find the PCM for about $25 and the harness for about $50 or less. VATS will need to be turned off in the PCM before it will run.

[mvfd70]

Originally Posted by DirtyLarry

Here is the harness you need if you go the 4L60E route. It would be the best money you can spend on this project besides a thorough engine cleaning and painting. When it comes to EFI conversions the biggest mistake everybody makes is skimping on a harness and trying to reuse the OEM harness.

http://www.howellefi.com/customer/ge...nsmission.html

$650 for a little bit of copper and a couple of plugs?!?! Holy crap! I think i'll take my chances on reworking a OEM harness. With all the info i've looked at so far I think i'll be ok with that.

[68GMCCustom]

Originally Posted by Sport/Truck

Then you just went in the wrong direction.
s/t

not necessarily....he could always go carb'd with it and use a GMPP/ or MSD ignition box to fire the coil paks....or...get the special water pump they make with a provision for a distributor (Ford style I believe)...no computer required.

[Clyde65]

I have a 4.8/4l60e in my 65, love it! If I may share some of my thoughts, I would go get an aftermarket harness (http://www.lt1conversion.com/products.php),and a performance tune from Nelson Performance. Yes you will pay around $500 for the harness and yeas you will pay around $350 for the tune, but from my experience, THAT is the only way to go for nice looking engine compartment and quality tune. No I dont work for any of these folks, I just did it the way you were talking, myself, then had a cheap place do the harness and PCM, then I went the route I just told you, I am very happy with the motor and all now, alot more pleasant to see and runs tons better.

[MARKDTN]

I'll put in another plug for Howell. I have a TPI harness from them and it is top notch. Nice people to work with too. Don't be afraid of Fuel Injection, it is really a great way to go. I have never done an LS type swap, but have done several TPI swaps and a few Ford swaps. Another great place for harness I'm told is Street and Performance, but they are pricier than Howell.

[DirtyLarry]

Originally Posted by mvfd70

$650 for a little bit of copper and a couple of plugs?!?! Holy crap! I think i'll take my chances on reworking a OEM harness. With all the info i've looked at so far I think i'll be ok with that.

$650 would be the best investment you could sink into this project if you want it to look and work correctly. So many people (and some with success) use a donor harness from a production vehicle but think about how stiff and brittle the connectors and harness will be from a 10 year old truck with almost 200,000 miles. That is a lot of heat under the hood for 10 years to wreak havoc on connectors, etc. I did a TBI swap a couple years ago on a ’72 C20 and started using a donor vehicle harness. About 30 minutes into reworking the donor harness (and after connector after connector broke) it became obvious it was a huge waste of time. The best $400 spent on that project was a fresh TBI harness from Howell.

There is a lot more to a new harness than just copper and a couple plugs. You are paying for the R&D these harness suppliers have put into these harnesses to research which circuits you need and which you don’t as well as easier taps into the OEM harness for power, ignition, and tachometer feeds not to mention the Delphi connector$ are not cheap individually let alone for 20 connectors, hundreds of terminals, weather pack rings, etc that go into building a complete harness. As Clyde65 stated, a new harness is the best way to get a top notch running engine with a clean looking install.

[ls1nova71]

Alot depends on how much money you have to spend, so with that in mind, the easiest route will always be the after market "plug and play" harnesses, but with ease comes price. Now if you're like alot of people and have more free time than extra cash, find yourself an original harness for a '99-'02 Silverado (try to find a truck one, Tahoes and Suburbans "sometimes" in those years will have drive by wire-DBW, you need drive by cable for what you have) then spend some time at this site www.lt1swap.com, it will walk you through the process of converting a stock harness to stand alone, or by using the factory under hood fuse box. It really isn't as hard as people make it out to be, it's just intimidating because it's alot of wires. But the reality of it is, if you take all the pink wires that went to the underhood fuse box, and put 'key on' power to them, then take the few orange wires and put constant power to them, it will start. This is of course after you have the VATS (vehicle anti-theft system) flashed out of the PCM. Brandon at lt1swap.com can also do that for you, for alot less than the big name places. I don't think I'm llowed to post prices so I wont. It won't be a perfect tune because you can ONLY get that by doing a "live tune" which is done in the car while driving it, but will be as good as any 'mail order' tune. I have personally put tens of thousands of miles on mail order tunes in the past, they are fine for the average person, but if you're trying to trying to shave off tenths of seconds on your quarter mile time, then that's where you need a live tune.

I've done alot of Ls conversions, it will be the best thing you've ever done to your truck. Just for a reference, you can check out my build thread on LS1tech. http://www.ls1tech.com/forums/conver...6-0-4l80e.html This truck I sold, but am now in the process of building a '71 swb with a 5.3 4l60e.

EDIT-I wasn't trying to put down what DirtyLarry said, I started typing my response before he responded, but I type really slow. I'm just offering suggestions.

[DirtyLarry]

Originally Posted by ls1nova71

EDIT-I wasn't trying to put down what DirtyLarry said, I started typing my response before he responded, but I type really slow. I'm just offering suggestions.

Hey, no offense taken. I agree with you, there are many ways to skin a cat. You can use a brand new sharp knife or sharpen up a rusty nail which ever you have the time, patience and budget to work with.

You did an outstanding job on that truck lsnova!

[mvfd70]

Well that does give me a little more to think about. Another question for those that have done this before. Should I stay with the MAF or get rid of that? This truck will be a driver/cruise around vehicle so I plan on keeping the motor stock. I don't need a hot tune or anything. Actually I want the best fuel mileage possible from it.

[Clyde65]

You will need the MAF, unless you go with a speed density tune ( more expensive and needs to be Dyno tuned I believe)

When I did my truck, I did the converted stock harness, it worked fine but was really ugly and it drove me nuts. I had a performance tune done on my PCM, without a dyno, and it improved my performance alot and my mileage went from 14MPG mixed to 16MPG mixed, 20MPG highway.

A couple things you need to be aware of Mvfd70, you will need an electric fuel pump and plumb it, just a Walbro255 will be fine as long as it will supply 58psi at the rail constant. Also you can use a TH400/350 but you will need to get a different flywheel and spacer to connect. BTW a 350/400 trans will not get you the best mileage, you would need an overdrive trans for optimum MPG.