1998 K1500...5.0 wiring vs 5.7 wiring?

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Manimal

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Ok, so I have posted about my misfires and all that I have done.So yesterday I pulled the heads off my truck..1998 K1500 5.0....exhaust valves were pretty crusty and I pulled #6 ex valve out and it 'MAY' be slightly bent, but not sure. But the p.o. did not do routine maintenance and there is a LOT of sludge in the lifter valley. I have been contemplating a 5.7 swap anyway and now even more so.
I found a guy parting out a 1998 Tahoe 5.7, '2wd'. He said I can have the engine harness,computer and exhaust for $150....my questions are...
1) Will the 2wd exhaust work on my 4wd?
2) What is the difference in the engine harness between the two engines and will it be plug n play if I swap the harnesses?(Tahoe engine harness in my k1500?)
Im sure I will have to have the ECU flashed for 4wd,gear ratio and tire size.
I am NEW to all this stuff and appreciate ANY help I can get.
Thank You
 

Manimal

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What about the 4th O2 sensor? And why cant I use the 5.0 exhaust and 3 O2 sensors and have the ECU tuned for the 5.7?...fuel and timing.
 

Scotty.92

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5.0l exhaust has 1 cat, and 5.7 has the dual cats. The 2 rear o2 sensors only monitor cat efficiency. 2 front o2 sensors work to adjust fuel trip.
 

Hogg

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The 4,3 and 5.0 have 3 precat O2 sensors, while the 5.7 and 454 have 2 precat and 2 postcat O2 sensors.
A Bank1 and Bank 2 precat then a Bank 3 precat sensor which reads BOTH Banks at once, then the single aftercat efficiency sensor.
There are some differences between the 1/2 ton 350 and 3/4 ton 350 wiring as well. The same wires are present, but the Banks are represented differently.

The rest of the wiring should be the same.

peace
Hog
 

Supercharged111

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Would be easiest to keep existing exhaust and bolt 5.7 in its place. Next, have the PCM reflashed so it knows it's now a 5.7. Truck would probably run if you just slapped the motor in though.
 

Koda004

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Ok, so I have posted about my misfires and all that I have done.So yesterday I pulled the heads off my truck..1998 K1500 5.0....exhaust valves were pretty crusty and I pulled #6 ex valve out and it 'MAY' be slightly bent, but not sure. But the p.o. did not do routine maintenance and there is a LOT of sludge in the lifter valley. I have been contemplating a 5.7 swap anyway and now even more so.
I found a guy parting out a 1998 Tahoe 5.7, '2wd'. He said I can have the engine harness,computer and exhaust for $150....my questions are...
1) Will the 2wd exhaust work on my 4wd?
2) What is the difference in the engine harness between the two engines and will it be plug n play if I swap the harnesses?(Tahoe engine harness in my k1500?)
Im sure I will have to have the ECU flashed for 4wd,gear ratio and tire size.
I am NEW to all this stuff and appreciate ANY help I can get.
Thank You
Ok, so I have posted about my misfires and all that I have done.So yesterday I pulled the heads off my truck..1998 K1500 5.0....exhaust valves were pretty crusty and I pulled #6 ex valve out and it 'MAY' be slightly bent, but not sure. But the p.o. did not do routine maintenance and there is a LOT of sludge in the lifter valley. I have been contemplating a 5.7 swap anyway and now even more so.
I found a guy parting out a 1998 Tahoe 5.7, '2wd'. He said I can have the engine harness,computer and exhaust for $150....my questions are...
1) Will the 2wd exhaust work on my 4wd?
2) What is the difference in the engine harness between the two engines and will it be plug n play if I swap the harnesses?(Tahoe engine harness in my k1500?)
Im sure I will have to have the ECU flashed for 4wd,gear ratio and tire size.
I am NEW to all this stuff and appreciate ANY help I can get.
Thank You


I have already been through all of this everything will be fine if you just drop in a 5.7 the only time you really have to worry about harness and computer is if you going to an automatic from a manual you don't need the exhaust system unless you want it my 97 k1500 came with a 5.0 and I put in the 5.7 everything is the same
 

Koda004

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You don't need to flash the computer everything is the same the only thing you have to do is when you go to read the codes though obd2 you need to remember that it had 5.0 so you can read everything everything from a 5.0 to a 5.7 is the same except for the bore
 
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