swap 4.3 to 4.8, v8.?

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#1
Make
chevy
Model
s10
Year
01
Miles
138k
Engine
4.3
hey guys, i have an 01 s10 4x4 auto with blown 4.3. also an 03 gmc fullsize 4x4 auto, with 4.8, v8. has a rusted frame cant inspect. excellent running motor. i know about the oil pan issue, and fan clearance issue, but not much more. will it bolt to the trans.? am i foolish to even try.? any feedback will be better than i have now. thanks, john
 

nickb2

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#2
will it bolt to the trans.?
I wouldn't see why not, both used a 4L60e. But the 4.8l also came with a 4L80e. So just make sure you have the 60e as there may be incompatibilities there.

But the big problem I would be more worried about is PCM/TCM issues. You are going from a v6 to an 8. Then you have to worry about transfer case issues. The 4.8l came with 4 different NVG transfer cases. None of which are the same as what came with the 4.3l v6. So the transfer case modules will not be the same. Wiring issues for both engines will be a nightmare to sort out. Programming the modules is a whole different story.

My humble opinion. This is not a feasible swap. You will need to modify pretty much everything from radiator to fuel lines. I don't think the v6 rad will be big enough to fit the cooling requirements of a v8.

I don't know if they make swap kits for a v6 to v8 engine harness. I know they make them for 4.8l to 5.3l and 6.0l. Those are easy to do. But a v6 to a v8 is just plain going to be an electrical nightmare to sort out. Fuel pump should accommodate flow, but then again I am guessing.
Then you have to think also about reflashing the PCM, and even if they are the same casting. When I worked in the tundra, I did a few swaps between 5.3ls and 6.0l in suburbans, those where easy cuz both were pretty much the same platform and flashing could be done as the same casting pcm worked.

Try LS1trucks.com. They may have better answers.

Anyway, what I am trying to say is that this is definatley NOT going to be a plug a play thing. You are in for a huge adventure with this. I certainly wouldn't try it.

For the price and frustration this will cost, I would be looking for a other 4,3l.
 

billr

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#3
^^^ +1

Any kind of swap is possible, of course, but I agree this isn't likely to be practical. A couple more considerations:

That vehicle never came with that V-8 stock, so even just a dealer "re-flash" of the PCM may not be possible; and no chance of finding a PCM from a JY that will swap in. Sorting out all the wiring differences to use the PCM from the '03 is probably the easiest way, but it may not communicate properly with the BCM, so that would have to be swapped and "sorted" too.

Good news is that Chevy is favored by swappers becuase parts tend to be common over a wide range of years and engine/trans types. Playing "mix-and-match" with Chevy parts is easy and inexpensive as it gets.

You mentioned inspections and rust, so I assume that is a safety inspection; but, what about emissions, will this hybrid have to pass emissions inspection of any kind (including just a quickie visual during the safety)? With that engine swap I doubt it will meet emissions.

As said by Nick, going to a Chevy truck-specific site may be your best source of info. We hate to discourage folks from coming here, but we also try to provide the best advice we can, and that's it for me.

Lastly, if this will not have to have any emissions testing, then consider doing this swap using a Megasquirt aftermarket ECU for the engine and the stock PCM to control the trans. Megasquirt can also control the trans, but that will raise the cost too high, I think. With any kind of luck (and soldering skill) the Megasquirt could be installed for under $500. Post at <msextra.com/forums/> for further info.
 

grcauto

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#4
I don't think you want to attempt this project unless you have a donor vehicle. Even then it's a tough build but can be done.
 
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#5
well guys you didnt let me down. i wanted the truth from ones who know. and bill it will need emissions. i havent pulled the 4.8. so i will pull it to the yard. i think i came to the right place. thanks a lot guys