I need info reguarding engine, tranny, rearend, transfer case, etc. I have an '04 Silverado 2500HD 6.0L, 4 spd A/T, P/B 4x4, 4.10 gears, 4l80e tranny. I do not understand all that I read, for ex. I have no idea if my engine is a LS1-LS2-LS3-LS6-LS7 and what is the difference between those and an LQ4. I only know it is a Vortec. Is it TBI or TPI. Does it have an aluminum block or heads, or is it all cast iron. I would like to know this so I know what to look for and what I can do when start to upgrade the performance. I have heard that adding an aluminum head to the 6.0 can push HP close to 400, but given the SS has an aluminum head, could I use head from it? Can I use parts from other engines on mine???