I just purchased a 2005 Chevy Express 3500 with a 6.0L engine that is bad. I was told that I could replace it with a 2006 5.3L engine without having to do any conversions does anyone have any input?

 

why would you? In theory as long as it has the same rpo code yes, if you have a helpful or knowledgeable parts guy at the dealer he should be able to look it up and tell you if the rpo/vin codes match

 

I thought that the 3500 comes with either the 4.8 or 6.0. The 5.3 is for half ton models.
In 2005 were the transmissions the same on all engines. When did the 6 speed one come out?
Computer might need programming etc. By far easier to replace with the same engine.

 

my input would be to stick another 6.0l in there. One of the best engines made, see many going 300-400k routinely.