My 1991 Chevy Blazer is still a work in progress. There are a few things I want to change as I continue building it into something that’s more capable off-road, while still keeping it usable on the street.
The first big upgrade I’m planning is changing the axle gearing from the current 3.42 gears to 3.90s. The Blazer has the stock 3.42 ratio right now, and moving to 3.90 should give me a little more gearing for off-road use. It’ll also make more sense with the larger tires I plan on running.
The other major change is doing something about the differentials. Right now, the Blazer is completely open in both the front and rear. That works fine for normal driving, but once you start getting into situations where traction is limited, having both axles open can become a pretty big limitation.
For the front, I’m planning to go with a lunchbox-style locker. The manual hubs I installed on the Blazer make this a much more realistic option for me, since I can simply unlock the hubs when I’m driving on the street and only engage the front axle when I actually need four-wheel drive. Since this is a vehicle that will still see plenty of street use, I think a lunchbox locker makes the most sense for what I’m trying to do with it.
In the rear, I’m leaning toward an Eaton-style Posi. I’d rather have something that’s a little more street-friendly in the rear while still giving me a significant improvement in traction off-road. Having a locker up front and a limited-slip setup in the rear should give the Blazer a pretty good balance between trail capability and everyday drivability.
Another upgrade I want to tackle is adding a rear roll cage. I’m looking at the DIY4X kits for this. The plan would be to weld the cage into the rear of the Blazer rather than just having a bolt-in setup. Besides adding some additional protection, I think a properly fitted rear cage will look right at home in an old K5.
None of these upgrades are happening all at once. This is more of a long-term build, and I’ll probably tackle things as time and budget allow. The gearing and differential upgrades will probably make the biggest difference off-road, while the roll cage is more about improving the overall build and adding some additional protection.
The Blazer doesn’t need to become some extreme rock crawler. I’d like to keep it relatively simple and reliable while making it more capable than it is now. These upgrades should go a long way toward getting it there.