Gears for a 4.2
 

Just wondering what rear gears I should get. It's a 99' 4.2 sclb with a 5 speed, (soon to be a 4"/6" drop), it's cat-less with shorty headers and a cherry bomb pro, stock 30" wheels and I'm pretty sure it has stock a stock 3.08 in the diff. I've been thinking 4.10's because I don't really care about top speed, and I can imagine 4.10's would probably make a fairly large increase in torque, but I don't want the truck to sound like it's about to explode while cruising at highway speed either lol and obviously that would increase engine wear and be bad for mileage as well. So I'm just wondering what you guys think the shortest gear I could get away with is?

You'll want to first check the tag on your differential to verify what's actually inside. Alternately, you can usually get the axle code from the door VIN/ID sticker, and cross-reference this. You'll also need to verify if you have the 8.8" or 9.75" housing if/when you decide to go shopping.

Post up your findings, and we can help a bit better.

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I put 355 in mine and it was alright. 308 was stock. Ended up going with a limited slip in mine with 373. Doing 100kms I'm at about 200 RPM so.. 410s would be fun too but good buy fuel and top end speed.

So which one did you do? I'm confused.