Why not just swap out the 4.8 for a 6.0L or 5.7L LS1 engine? You will gain more than doing all that work to the 4.8. I have seen guys sell complete 6.0 truck engines for less than $1000 many times. I got my 98 LS1 engine and transmission for $1400. Bone stock the LS1 puts out 400 hp at the crank.