5.3 liter to a 4.8 swap

[James Kotowicz]

I made a mistake and didn't look a little closer. I have a 5.3 liter in my 2000 silverado. This engine is extremely tired and needs a lot of help. I decided to buy a used engine and was told is was a 5.3. I wanted to reseal the engine. To make a long story short i found out it is actually a 4.8. The question I have is will my 5.3 PCM work on my 4.8 or do I need to have it reprogrammed? I plan on putting the 5.3 back in sometime in the future. ( make take me a year or so do though. I'm not looking for monster power. The truck is a daily driver for work and on the weekends I use it to tow  boat. Thanks for all the advice.

[Brian715]

That stinks. How do you know it's a 4.8l? Just curious as they are stamped 4.8/5.3. the only difference is the stroke as far as the block is concerned. Anyway, it will probably run when you get it in, but not 100%. Probably should plan on getting it tuned. 

[swathdiver]

17 hours ago, James Kotowicz said:

I made a mistake and didn't look a little closer. I have a 5.3 liter in my 2000 silverado. This engine is extremely tired and needs a lot of help. I decided to buy a used engine and was told is was a 5.3. I wanted to reseal the engine. To make a long story short i found out it is actually a 4.8. The question I have is will my 5.3 PCM work on my 4.8 or do I need to have it reprogrammed? I plan on putting the 5.3 back in sometime in the future. ( make take me a year or so do though. I'm not looking for monster power. The truck is a daily driver for work and on the weekends I use it to tow  boat. Thanks for all the advice.

They run the same camshaft (assuming the new engine is an LR4) and it should start and run fine.  You may see issues when you get on it, just speculating as I have no direct experience.  You can ask over at Performance Trucks forum too.  Others will come along here who'll know too.