vortec v6 to vortec v8 swap

[grezzmky]

I currently have a 2000 s10 4X4 blazer with the 4.3L automatic and recently acquired a 96 5.7L from a 1500 4X4 automatic with computer and harness (wires to trans cut) and good computer. My plan was to use the 5.7 computer and engine and the 4.3 harness with added wires for the 2 additional fuel injectors and extra O2 sensor. Is this going to work or were there too many changes between the 96 and 2000 motors or simply too many differences between the S series and K series trucks? I did plug the v8 computer into my harness to see if the plugs fit and they do. I even stared the V6 on the V8 computer and it idled (not on all cylinders) but did nothing then throttle body was opened. The oil pressure gauge worked but not the temp or fuel gauge. Also the shift indicator did not work. The computers are both black but the 96 5.7 computer has a fifth )5 or 6? prong) plug on it but only two black wires plug into it from the harness. also what tranny should I use? Thanks a lot in advance. haha, one more thing. What about using the v6 computer and reflashing it for a V8...?

[ChipsByAl]

The PCM's are different as is the wiring harnesses. EFI Live can program the 2000 model year Vortec PCM that you have in the truck now. If you can find a 2000 5.7 V8 tun file that matches your OS you can swap the calibration segments to run the V8 with your PCM. The only wiring mod is to add two wires from the PCM to the V8 injector connector. Not tuff at all.
Al

[grezzmky]

so use the v6 harness + 2 injector wires and the v6 ecm, correct? what about the transimisions? just use the v6 one? What about O2 sensors?

[ChipsByAl]

The O2 sensors will still work, they may need to be put in the exhaust in different positions. The 5.7 had dual cats with an O2 sensor monitoring each. For model year 2000 you will need to locate a "classic" C/K type Tahoe Limited/Yukon etc, not the "Silverado" style to clone. One thing to consider is your cluster. Yours is a "smart" cluster and these other vehicles have the old design that has individual sensor's for each gauge. Maybe Paul or Ross can help with this potential issue.
Al
Note! Make sure to check your local emission compliance laws before starting your project.

[grezzmky]

what about using all the v6 sensors in the v8?

[ChipsByAl]

The MAF is bigger, crank sensor and the HVS high voltage switch "distributor" is different. The throttle body and hardware is the same.
Al

[ZR2_350]

You will want to unplug all of the V-8 injector wires from the computer. Do the same for the V-6. Use the injector pod from the V-8, which will have all the wires you need. the color code is exactly the same. All you have to do is find the correct location in the computer and your done. The Pink wires, you will have all 8 from the V-8 pod, but only 6 from your existing harness. Tie all the pinks into the V-6 harness and your done. You can use all sensors from the V-6 on the V-8 with the exception of the MAF( but you could still use that too).

When you get the computer flashed, You will want to keep the base S10 tune in it, and transfer over the injector segments. All of your existing electronics( controlled via computer) will not be harmed. Transmission settings will stay intact also. You can change those manually if they don't fit the characteristics of the V-8. No worries with the O2 sensors either, you will keep the stock amount in the stock locations. Unless of course you redo the entire exhaust, then you can put them where you want, add or delete them too.
You will have to use the V-8 style knock sensor( mounted to the side of the block near the starter, and you will have to use the v-6 oil pressure sender, so be carefull when pulling the engine, as it can get damaged when removing the motor. The sender is located right behind the distributer on the rear intake rail.( where you would either put the cork/rubber or rtv sealer on when installing your intake manifold. Pay attention to the rear of the heads also, there are several grounds, and right behind the driver head there is the knock sensor. The V-6 knock sensor uses 2 wires, and the V-8 uses one. So if you have the connection from the V-8 harness, you can remove the V-6 style and repin for the V-8.

Not sure if you have the expansion tube or whatever it is called, it connects to the exhaust manifold, and then to the intake manifold. If using headers, you will have to delete that, or plumb it into the new headers. Or, you might be able to use the stock exahust manifolds and no fabrication.