06 rcsb with a 4.8, nothing fancy cai, flow 10series, rims and tires. Anyhow I'm lookin at dropping in a 6.0(w/ a cam and headers) and sticking with the 4l60e. My question is with the 4.8>6.0 do I need another harness and pcm or could I keep the existing harness and flash the pcm? Since the 4.8,5.3, and 6.0 very similar thanks