The 2002 S10 was 100% stock and had 2,700 miles on it when I purchased it off of Ebay in Febuary of 2003. I drove it until I had purchased all of the components needed to actually get the engine and transmission setting between the frame rails(engine,transmission,accessories,radiator,cooling fans). On May 20,2003, I  backed the truck into the garage under the power of the 4 cylinder engine for the last time . It had 9,048 miles on the odometer(still under the factory warranty). It took a total of 4 months to complete the project . I could have completed in 2 months but it took longer due to taking pictures and writing the manual along the way .On August 28th ,I drove it out of the garage for the first time with an Ls1 under the hood. I had a few bugs to work out (which is usual) for the first couple of days but they were soon worked out. I drove the truck everyday for 6 months until I sold it Febuary of 2004. I never had the first problem out of the install and it got  26 mpg on the highway !!!!! Not bad for a 345hp truck !