Craigslist sanity check: 4L80e + 5.7L SBC 350
 

Searching for a donor engine for my Chevy 3100 build because I've realized I have to do too much to keep the stock 4.3L v6 then have to do it all again for a v8 swap later. A craigslist find came up and the guy says it has about 100K miles with a 4L80e 4x4 transmission. Came out of a rusted frame 1/2 ton 1996 pickup. Guy wants $1100 for it all with ECU, wiring harness, alternator, etc.

Biggest issue I see is the 4L80e is 4x4 and I would need to be converted to 2wd. Anything else I'm missing? Seems a few trucks have put this engine and trans combo in. I also noticed it doesn't seem to be TBI which my research tells me is a good thing because it gives me more power enhancement options later.

Engine serial: 10243880
Trans: 7KC-D7 sn: 0322 848497


https://farm5.staticflickr.com/4223/...659745f9_z.jpg

https://farm5.staticflickr.com/4263/...97592447_z.jpg

https://farm5.staticflickr.com/4272/...7604a6e4_z.jpg

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

Im not sure about the conversion from 4x4 to simple rear wheel drive, but youre right about that engine being versatile. For $1100, engine, computer, and transmission seems like a good deal. Did the seller say why he jerked the driveline? IE....engine knock? truck rolled over?

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

I'm not sure about the 4x4 conversion either. Looks like its easy to go the other route, 2wd to 4wd because you cut the tail-shaft to fit the converter. Price wise, the guy is offering the engine alone for $750. I called a local shop and they'll convert the 4x4 for me for $1000 lol. At that price, I could get a refurbished 4L80e a lot easier. Maybe I'll just take the engine and leave it at that. Seems like transmission options are a plenty and if I don't have the $$ for the larger one, I can fit a 4L60e on without too much trouble.

I was trying to justify the extra $350 for the transmission thinking that was a deal. But it may just be a headache for me. Maybe I should take it and turn right around and sell it for $500 on craigslist lol.

Reason I was given was the truck was rusted out but the engine was fine, so they pulled it and scraped the truck.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

Well, she's mine now and very excited to have a v8 going into the build. I realize its a diversion from my original project plans, but hopefully not too much of a problem. My initial thought is to try and bench test the engine before putting much money into it just to be sure she's sound. Looks like I have all the necessary components to turn it over. Wiring is my biggest question mark...

The engine harness came with but I just realized there is no fuse panel, just the back side from the engine bay. Should I just get a new harness or is there a way to save this one? Maybe a generic 20 wire and steal all the good connectors off the existing harness?

https://farm5.staticflickr.com/4231/...e7b9fff0_z.jpg

https://farm5.staticflickr.com/4255/...453e9795_z.jpg



https://farm5.staticflickr.com/4232/...d6598f70_z.jpg

Just the engine side of the fuse block
https://farm5.staticflickr.com/4021/...e9619f5d_z.jpg

The ECU was cut from the harness. That's not so good.
https://farm5.staticflickr.com/4056/...3c56fa53_z.jpg

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

OH and in conversation, the trans was a 4L60e, so I'm glad I turned that down. I think I can find a 2wd 4l60e pretty easily... maybe I should start an engine build thread haha

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

You were wise in your not taking the trans as you usually end up with a full rebuild on the trans to change the tail shaft. I've changed a two wheel drive turbo 350 to a 4 wheel drive setup before by pulling the guts out of it, swapping tail shafts (from my brothers burned up trans) and putting it back together with new seals and gaskets.
That 4le60 would have been a real can of worms to swap out. Not a big deal for a guy who benches the trans and swaps tail shafts in the process but a big deal for you and your wallet.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

just glancing at it, that looks like a TBI computer and the engine is a spider poppet valve. can you find where he cut that connector and match it up? a 96 engine should have what they call a "black box" pcm. the yellow tape on there makes me think he gave you an airbag computer.

now that I look at it, it appears you didnt get the PCM, I can see the 4 plugs in the harness. in this picture.

https://farm5.staticflickr.com/4021/...e9619f5d_z.jpg

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

Yeah I definitely feel like something is missing in the current setup. I've spent the day researching how, or if, I can convert this engine to a carburetor setup for ease of wiring and more HP. Since the biggest hurdles are: Wiring Harness, Fuel Pump, and electronic transmission, I may be in luck. I have a 700r4 from the S10 which would work with a carbureted setup. I didn't get the fuel pump, so I need one anyway, and this wiring harness looks like it would cost more to fix than it would to replace.

Man am I in deep now! :sumo:

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

if/when i finally get around to doing a vortec swap im definitely going to buy the entire truck. all the little things that were cut or left on the truck adds up. i bought a 91 silverado off a guy for the engine and trans, he already pulled the parts as he was going to use it on something else but bought it all.

distributor was missing, oxygen sensor missing, temp sensor missing, starter missing y-pipe missing, ac compressor missing computer missing. he owned a shop so im sure it got picked though the year it sat there. but yeah sucks buying loose stuff

luckily i have all that stuff laying around but if i had to buy all that stuff new my $600 parts truck just went up to 1000, maybe more

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

That's a CFI, worse than a TBI, which are actually pretty good.

96 was not a good era for the SBC IMO. you don't want to to try to use that CFI deal, it's a PITA from one end to the other. I see that it does have a distributor in the traditional SBC loction, that helps. Count carefully how many bolts are holding the intake manifold on, it'll be either 8 or 12. if it's 8 it might be an early Vortec, which is a good thing. Look at the back of the block, on the bellhousing flange behind the left head. there should be cast in, not stamped numbers there. post them or a pic of them.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

Thanks for the info. I count 8 bolts for the intake manifold. 4 at each end. I also had the casting number checked and it says Gen I vortec 4 bolt main, roller cam with ZZ4. That seems to be a good thing: 10243880 is the casting #.

I'm trying to price and part out what I'll need to convert the engine away from all these electronics. Intake manifold, carburetor, HEI Distributor, etc... I'll post a parts list here to get some feedback so I'm not throwing money down the tube trying to make this engine work.

Jegs 20 circuit universal wiring harness. $270:
http://www.jegs.com/i/JEGS-Performan...annel=Shopping

Intake Manifold, Edelbrock Performer 2116 Vortec: $230
https://www.summitracing.com/parts/edl-2116/

Carburetor Edelbrock 1406 600cfm/electric choke: $334
http://www.summitracing.com/

Hedman 69520 S10 v8 Headers ($180):
Hedman 69520

Fuel pump: Holley Red Electric $120
https://www.summitracing.com/parts/h...01-1/overview/

Oil pan...

Oil Pump: $23
https://www.summitracing.com/parts/s...-summit-racing

Oil Cooler bypass adapter ($25)
GM part 19299222

That should be it

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

Carter p4070-
https://www.summitracing.com/parts/crt-p4070

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

Thanks! That helps.

Adding to the list of needed parts, it looks like the alternator and power steering booster I was given aren't the ones for this engine. So I'll have to add those accessories and the necessary brackets. At first I was thinking of just looking up the GM stock stuff, but now that I think about it, there's really no reason to stay specific to the original truck the engine came from. Time for some shiny stuff!

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

That is the stock Vortec CFI setup. As stated, not great, but not terrible either. That engine will be equipped with Vortec heads, probably the best factory SBC head ever produced. Converting it over to a carb'd setup isn't too difficult. For the HEI distributor, I would look into the units sold by Skip White Performance, relatively inexpensive and decent quality. I've used 3 of them on my drivers, and we have 2 or 3 in our dirt track cars.

For reference, that Carter fuel pump above will be very noisy. I ran one in my 1978 El Camino and it was absurd how much noise came from that thing, so be prepared for that.

For a good front engine accessory drive, find an 88-95 305/350 TBI pickup and pull everything off of it.

While you've got the engine out, I would put an oil pump and timing chain set in it.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

I'll keep an eye out for a quieter fuel pump. No need for the extra noise to save a few bucks. I'm afraid the GPH from that pump is a little high for a 600cfm carb anyway. Good call on the oil pump and timing chain. I didn't even think of that. Low cost items for peace of mind

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

my wife laughs heartily when I say this.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

The box pictured with the yellow connector is the DERM, the "brain" for the airbag. The yellow connector is a clue but the giveaway is the yellow tape wrapped around the harness. The PCM would be attached to the four connectors, red, blue, clear, and black, that are below the fuse box in the photos.

The CSFI systems had some problems but by this age most of the issues should be gone. We are retiring six buses this week with those fuel systems and they have from 291k to 397k miles on them. There are problems with the intake gaskets lasting over time but we've found that using the Fel-Pro perma-seal gaskets provides very good results.

A carburetor based system will not provide more power unless you change the cam. The stock CSFI intake and fuel system makes reasonable torque and is good to somewhere around 380 hp. That engine will not have a ZZ4 cam unless it was installed by a previous owner.

The steel timing chain and gears will usually last for a long time We have never changed a set in the L31 Vortec engines here. If you remove the timing cover to replace the timing set be prepared to buy a replacement. The plastic covers usually break upon removal.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

That's some great info! thanks. The purpose of the carb was more for removing the complexity of the system for me as a garage mechanic. The alternative at this point is to get a very expensive replacement wiring harness just to get it all reconnected. I think the painless wiring harness is a little north of $1,000 without the pcm

I wouldn't even know where to begin in choosing the correct cam for a truck to push over 350hp. Would be nice :)

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

I'm not trying to sell you one way or the other but I think it's a good decision to build the truck with future maintenance and repairs in mind.

Holy mackeral! That's crazy!! I've done plenty of harnesses over the years. I can't believe people pay that much. Maybe I should retire from running the fleet and start selling harnesses.

The Vortec heads flow well. The LT4 HOT cam is one option. Combine it with 1.6 rockers and you could end up near 400 hp with minimal additional work.

Some light reading:

http://www.superchevy.com/how-to/490...e-roller-cams/
http://www.superchevy.com/how-to/678...cam-355-build/

If that seems interesting then there are other options for springs.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

Wow, that is neat to know that I could get there. The article wasn't as detailed as I would need to even attempt such a thing though. They talk a little about the one piece main seal needing modification and some machining of the spring mounts. All a little out of my tool and knowledge range. I'm happy for now just knowing that down the road I can give it a shot or have someone do it when the truck budget is replenished :) For now, I think I'll notice enough of a difference over the v6 4.3L currently in the truck.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

just install the Eddie manifold and a small carb and run it. This is a real good choice for a street performance carb:
http://www.speedwaymotors.com/Holley...oke,59079.html Electric choke, vacuum secondaries, 600CFM will feed a a 350 to 6000 RPM

I personally have had terrible luck with the Skip White HEIs. on other sites they're referred to as the "ebay $50 Fake HEI." I've had 3 of them fail on the first drive, 2 others within weeks. the GMPP HEI often called the ZZ4 HEI is under $200 and will likely last your lifetime. A quality module for an HEI costs more than the whole Skip White HEI. Wonder if that's got anything to do with it. The GMPP unit, buy it, drop it in, run it. Do not replace any of the electrical parts in it at all.

if you buy an electric fuel pump check the output pressure you want about 6 lbs. The GPH flow doesn't matter much as long as it's a 6PSI deal. If it's any more than that you'll have to run a regulator, another source of problems. You don't want one of the $25-35 units from an auto parts store, they're garbage. you'll have to carry a spare with enough tools to change it out if drive it anywhere more than a few blocks.

Really, skip the Skip White HEI. if you do get one of these make sure your AAA is paid up.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

That's the exact carb I was looking at. Wasn't sure if I should match up the intake manifold with the eddie carb or not. Seems to be mixed reviews on Edelbrock carburetors.

Wiring harness has been ordered, so that's a start.

Anyone have part numbers for the low profile oil pan and headers? The S10 swap thread just says speedway headers. This thread is kind of turning into a v8 build thread haha.

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

Piecing together parts, but I may have missed something. I have a battery, starter, ignition switch, and the GM HEI that came from the TBI engine. Is there something that is supposed to be between the HEI and the starter? Trying to test the engine with the least amount of wiring and accessories necessary. I found a few diagrams, but they all talk about having a relay or coil except for this one:

http://www.ss-restoration.com/upload...031804.jpg?902

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

It looks ok. What is not working?

Re: Craigslist sanity check: 4L80e + 5.7L SBC 350
 

TBI doesnt use HEI, and neither does the CFI that is on your new engine. HEI is a "coil in cap" ignition that was on engines prior to TBI. A TBI distributor will have a hall effect switch and a separate coil, and the CFI will just have an angle sensor for the PCM.

if you want an HEI, you will need to buy one.