I might need to change to DBC so I need to know where to start. It is an 8.1 Vortec, bored out, ported heads, tuliped valves, roller rockers, Raylar 203 cam, modified ported intake, and 102mm TB, with manual trans. If I convert to DBC my P59 pcm does have the IAC driver. I have a pcm read from a DBC 5.3 I used to have in my C10, but I think I might need a 6.0 DBC express van tune. I don't know if I can use either because I have 503ci and a 102mm TB going on it so I don't think the IAC or TPS tables will work well. Now the pcm does have the IAC tables filled in on my 06 8.1 but they are ran all 8.1's on DBW. I haven't finished my harness yet on my 05 pcm for the chevelle, until I find out if I can run a DBW NW102 or need to go DBC, so I haven't read the 05 pcm yet. But the pcms should be the same other than the 05 had a 5 speed ally and the 06 has a 6 speed ally, which I am running a stick. Thanks!