I recently purchased a 2003 3500 SRW SWB 4x4 HO 6spd. I am planning on changing the oil in the near future and am in need of some suggestions on a good non-synthetic oil to use. I am planning on using synthetic after I get more miles on the truck, and was also wondering how many miles I should put on before switching to the synthetic. I have heard that you should put 10K on before going to synthetic. Does this sound right?