Would these gears be ok? I need more grunt to get up some hills here in the rockies.

 

They would work great offroad but forget about driving on the highway. I'd go with 4.10s instead.

Just an FYI, ZR2s came with 3.73s and 31s stock. I never had a problem offroad with that combo, though I wish I had 4.10s with my 33s now.

 

thank you for your input. I have never changed gears in a vehicle before so i have no clue what im looking at. My friend has a zr2 and we had some issues with it going up one of my favorite trails thats why i went bigger in my thinking. I never drive more than 60 or 70 miles on the hiway how would the 4:10s hold up to 65mph I would really just be looking at high rpms right? Reasonably I could just go slower?

 

Yep, the lower the gears (higher number) the more RPMs you'll be turning on the hwy. If you've never changed gears yourself, either have it done or have a buddy with some experience help. Keep in mind, to change the gears up front you'll have to drop the front diff from under the truck.

I would venture a guess that with 4.56 gears and 31s you'll be doing around 2500-2700 rpms at 65ish. Not terrible but your mileage will suffer greatly. You will feel a boost in the pants taking off, though. And it will really help climbing trails offroad.

Or, you could try 4lo on those steeper hills. I know there have been more than a few times I've needed 4lo because of climbing steep hills just to keep the rpms up.