I have a 99 Silverado with a "05" 5.3 H.O; running on my stock 4.8 ecm..I also have a 2002 ECM #12200411 that came out of a truck with 8.1 in it, I would like to use this ecm on my truck if possible? And what would be the best why to do this? All input could help please.....need to start my tune with one of them , getting HP Tuners..

 

Take the PCM ending in 0411,and flash a 02 5.3 file in there.You will need to do a write entire (not write calibration only) to do this.Anytime you flash a different OS in the PCM,you must do a write ENTIRE.
If you need a stock 02 5.3 file or any help,just send me a pm

 

Just a note, the 99 truck came with 21 lb injectors, and 00 and up are 24.7, so you should either adjust the tune accordingly, or upgrade to some newer injectors BTW, installing an 02 PCM in my truck cured the false KR problems I was having after my cam swap with my original 99 PCM.

 

P.M sent....I did use the 05 5.3 injectors just changed my fuel rails..

 

I also like using the values used in the 05 tunes when the tables match up...