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How to swap a Vortec 350 into a 4.3 S10/Sonoma

272193 Views 210 Replies 56 Participants Last post by  Rhotpursuit
Doing a little write-up while it is fresh on my mind. This will be specific to 2000-2003 s10 with the 0411 silver computer and 2wd......but a lot of info will cross over into other years.

First, the engine:

You want 1996-2003 350 out of a full-size truck or an express/savanna van. If it is out of a 2500 or larger pickup, you must change the oil pan to 1500. It will not clear the cross-member.

Things you want to do before install to the 350:

Well, make sure it is a good engine. If it has too many miles on it, I will rebuild it just for peace of mind, even if it is a good running motor. You do not want to be pulling this motor again in 20k miles.

AT THE VERY LEAST, change the intake gaskets.

I would also recommend changing the spider injector to the updated version.

Check the distributor gear for wear and the shaft for side-to-side play.

Change the water pump. They are $40 for a brand new one. Again, peace of mind.

PAINT IT. This will make it look much, much better when installed.

Things you will need before you start this:

Motor mounts.
Many different companies make them, including JTR and Current Performance. I went with the JTR.

Four options here. Hedman, Sanderson, eBay stainless.....all shorties. Or, if you dare(you will have to move your fuel lines), long tubes. I used the Heddmans. You have to specify bigger flanges with the heddmans. They come with 2".

Most people use the 1986-ish Corvette radiator. This requires cutting on the core support. And requires an adapter for the lower radiator hose. I used the stock 4.3 radiators. I figured if I had to cut, I might as well make my stock one work. That way, I could use the stock tranny cooler and oil cooler. There are other options that do not require cutting. Current Performance makes one that fits in the stock location. But it was 500 bucks. I will post pics of the stock radiator frenched later in this post.

I used the stock clutch fan that was on my 350. My 350 came out of 1996 2500HD. You may want to go with an electric fan...I will be later when money allows.

Here are the electric fan options.
Using the stock radiator(16x26 inches), a 2000-ish Dodge Intrepid fan will fit PERFECT. And I will keep it cool. Also only pulls 14-16 amps. Also, a mid 90's Volvo fan will fit perfectly.....but pulls around 40-50 amps. You can also use an early-mid 90's Nissan Quest fan. It fits like stock and pulls only 20 amps.

If you go with the Corvette radiator(16x23 inches), your options change. A ford Taurus fan fits it perfectly. The 1995 and below single fan dual speed ones. You can also mod the Nissan Quest fan and make it fit.

The biggest thing to remember here is 1 or 2 aftermarket fans without a shroud WILL NOT COOL IT WITH AC. You must run a shrouded setup to get maximum airflow over the radiator.

AC condenser.
No matter what, when you move the radiator forward, your stock condenser will not work anymore. Some people modify the hood latch bracket and move it to the front of the core support. Another option is the Current Performance one. It will fit behind the core support.

With a 2000 and up, you can use your factory 0411 computer. It will need to be reflashed. Many places do this. I tried Wait4me and got screwed. It did not work. Engine only ran on five cyl. I now have a Current Performance computer, and it runs great.

Companies that do this:
Current Performance
Black Bear Performance
And many others...

From 2000-2003, use your 4.3 harnesses. You only have to add the two injector wires, a one-wire knock sensor, and separate the low side ground for the O2 sensors. I will get into wiring specifics later.

The 4L60E will work fine. I am sure the 5-speed will work fine too. You will have to get different bell housing bolts. The 4.3 are metric, and the 350 are not.

The stock 4.3 starters will work fine on either flexplate as long as the 5.7L was from a 1500 truck with 4L60e. My engine was from 2500 with 4L80e, so I could not use the flex plate. Again, the bolts on the 4.3 are metric, and the 350 are not.

OK......next post will concern installation. More to come.
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You don't pull the dash and interior wiring out. You unplug the harness from the starter, ground to frame, battery, transmission, o2's, and unbolt it from the fuse box. Throw the harness on top of the engine and pull it. When it's off unplug everything, get the 411 plugs, and repin it that way. You don't have to have ABS and there's a thread on here on how to delete it, VATS has to be deleted with tuning software, idk about evap, you'll want to delete the EGR if your truck has it.

I'm pretty sure the dash won't bolt to a 1st gen. I THINK you can use your stock gauges (Tippman would know). I can't remember what you do with the fuse box to get power to it exactly.
Thanks Justin, and I hope that new treatment is helping you out:D
Np. For the first week my chest was constantly tight and I had a cough. They said it was normal though and the pill could take a few days to a week to start working. Well more like two weeks for me, but I've had more energy and the huge amount of salt in my sweat is almost gone. Used to when is sweat and it rolled down my forehead it would seep into my forehead and pretty much feel like I cut slits in my forehead with a knife and poured salt on it. So yeah pretty happy about that lol.
Oh and I reread what you're doing. You'll probably have to remove the dash on both vehicles in order to get the 96 gauge cluster in there. Like I said though I'm sure there's a way to keep your stock one.
Ive done minimal reading up on this and the only thing that concerns me is the wiring harness lol seems pretty straight forward. I MAY end up doing this one day.
If either of you need more info I have a ton of links on it.
Dude, reading about the wiring would be like reading gibberish. Unless its like a picture book with lots and lots of pictures, I wouldn't be able to understand it unless it was physically in front of me. Idk that's just how I learn.
Yes Michael, that's the same for me, except I don't get it if it's sitting in front of me either:haha: I just plain hate wiring!
I guess if I go at it by the wire numbers that's probably better for me, I'm a numbers guy.
Well the 411 swap is all numbers and the injector pod is numbered. All you have to do is repin the PCM, run two wires from the pcm to the V8 pod, repin pod, tap into two grounds at the pod, run two wires for e-fans.
That's Greek to me, but I took a year of it. Actually my dad's an electrician and if I have any questions about wiring I can just ask him. :p

How about those links ZQ8Justin?!!
Thanks Justin, I'll have to check that out. Just to make sure, I can put wire 109 into the pin for wire 109 in the 0411 connector, for example, is this correct?
Just curious, why can't you just hook a 350 vortec up with the 4.3 wiring and computer on a 96 S10? Can you add the 2 extra injectors in somehow, or use a 1/2 ton computer and injector harness with the S10 harness? I'm wondering basically what the difference is between the two.
No, they're all different. You'll need to pm lextech and get the spreadsheet from him. He has mad of so that it tells connector 1 pin 3 goes on the black box goes to connector 2 pin 22. That's not correct, it's just an example.

Nah that's what you do. You use your 4.3 harness (4.3 and 5.7's are nearly identical) and run two wires from the PCM to the V8 injector pod. The. At the pod tap into two ground wires.
No, they're all different. You'll need to pm lextech and get the spreadsheet from him. He has mad of so that it tells connector 1 pin 3 goes on the black box goes to connector 2 pin 22. That's not correct, it's just an example.

Nah that's what you do. You use your 4.3 harness (4.3 and 5.7's are nearly identical) and run two wires from the PCM to the V8 injector pod. The. At the pod tap into two ground wires.
You mean with the 0411 and its wiring schematics tho, right? This won't work with the black box if I understand correctly?
What are you asking??? What are you wanting to do???
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