4.3 to 5.3 swap?

1quick

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on a 2003ish vintage 4.3 powered truck could you swap to a 5.3 and run it off the stock computer? not sure on what ignition the 4.3 had, or would you have to swap the harnes out for a v8 harnes
 

Turbocharged400sbc

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:nope:
the 4.3 is a non binary crank trigger motor and no you cannot run a v8 on its computer or wiring harness you will have to swap everything in
 

Fouled Plug

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I dont believe you can run the v6 computer. Also i believe the v6 transmission has different guts.
 

Mr_Roboto

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I'm wanting to debate this partly, the box used is an 0411 on the later stuff which is the standard LS car box. You'd definitely need a flash though at the least to run it. You're also talking a significant amount of wiring changes, enough I'd probably want to reverse engineer the harness off the LS engine and splice it into the body harness on the truck. They had the gauges controlled by the ECU, so you pretty much need something for that unless you're shoving some Autometers in.

Not sure but the tranny should be the same. The early ones aren't the same, but that's like 92, 93-94, 95 and then 96+ electrically. A 4.3L V6 will use a "V8" style trans with a similar TC (the LS is longer I believe) versus the "4 banger/60 degree/3800" variety I think you're mentioning which has less splines on the input shaft. Supposedly you can use a Canyon/Colorado converter as a cheap upgrade if you go this route, or they made spacers for a 4L80E you can use. 94 and later had the same clutch counts as the V8s, so you should be good there.
 

1quick

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I have a hard on for something else already lol, im selling all my 3800 junk to start on something new in the spring
 

Mr_Roboto

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what about a vortec 5.7 ?
Flash the ecu and run 4 wires for the injectors and splice a new intake connector in. Problem is the spider limits hp if used so you really need an intake manifold.
 

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