Do you not know how google works? There are all sorts of gear ratio/RPM calculators out there. Whoever says you'll be redlining with 35's and 4.56 with (assumed) overdrive in the 4L60E is an idiot. Off the top of my head I'm going to guess that you'll be right around 2500RPM at common freeway speeds.
I like J J's answer. But in all seriousness, why do you need to go faster exactly? It's lifted with 35'' mud grapps which are terrible for road use in the first place. This truck won't be $hit for mud once you gear it up buddy.
If it is faster you want to go then something that starts with a two point would do. But you won't like the time it will take you to get to that faster speed. And just to show you up a bit, throttle body fuel injection is electronic fuel injection. Nothing like a dumb a$% with a old pickup truck.
I have a 1995 Chevy Silverado. It's lifted with 35" nitto mud grapplers. This is the throttle body injection not electronic fuel. It has 3:73 but I want it to go faster. I wanted to put 4:56 but people say I'll be red lining at 5,000 rpm. What would be the best gear ratio. Thank you