The 02 Sierra currently has a 5.3l in it and i can get a good deal on an 8.1l. the 8.1 came out of a 2002 Chevrolet Avalanche 2500. I didnt know if this engine would fit in the Sierra, but i heard from a friend that since they are both Vortec engines, all the wiring will work, you just need to reprogram the computer, but he is just a backyard mechanic so i dont know what to believe.
Will an 8.1l vortec fit in a 2002 GMC Sierra 1500?
- Thread starter Gearhead
- Start date
Molson02536
New member
The 8.1 vortec would fit, but your going to have to also replace the ECM or get yours flashed to match the parameter to the 8.1 liter vortec to have it run properly. The other thing also you have to keep in mind is the transmission on the 8.1 i believe is mated to a 4L80E and the one you have mated to the 5.3 is a 4L65E so your going to have to do a custom program to your ECM to match the transmission' s performance to your engine's performance.
The best thing for you to do is to replace the CAM shaft (LS1 Hot Cam 219/228 .525"/.525" @.050" LS6 Springs) to wake up the engine's performance, and do a dyno tune. A custom tune can get rid of the torque management to match the engine and transmission's performance.
http://www.youtube.com/watch?v=h7O-V1fffjw&feature=related
http://www.youtube.com/watch?v=RgjM9bme3ok&feature=related