His intermediate pipe is 3". Everything after the muffler doesn't affect performance.

 

I have 3.73s now. The only reason I was thinking of 4.10 over 4.56s is that I didn't want to go too low of gears for any highway driving that I do. Right now Im already pushing just slightly under 2k at 70 mph I dont want to make the mpgs to out the window. But if I wouldnt notice that much of a diff just by jumping up to 4.10s it prob wouldnt be worth the money I dont think. How much rpms would 4.56s be running with my 285s and then with the potential 33s that I want? How much hp would 4.56s feel like going from 3.73s to them? Like 30 or 40 hp? I just dont want to be dropping 3 mpgs or anything, already lost 2-3 mpgs with my gryphon which is suppost to be checked out from bill.