I couldn’t tell you what I would have done with that ride, but back then 35’s were big tires. Anything over that was huge.

I always liked the look of 35’s on a half ton Chevy. This truck looks good in pics bit in person it’s a little much

Shoot what gears does it have in it? If they haven't been changed, with 37's that thing will drive like it has overdrive compared to a 3 speed with stock tires... but getting it going will likely suck.

3:56 gears is what I've been told

You might want to pull the diff cover and check. I've never heard of 3.56. Probably 3.08 or 3.73 gears from the factory - maybe 4.10.

I had 4.10 gears with a TH350 and 37's on a 76K5 with stock 400sb. It ran well, decent low end and cruised nice around 62mph.

Chevy did have 3.55 gears. I had an '89 Blazer, and I believe it has 3.55 gears. Ran great with 33's. I would suggest lower gears with anything taller than 33".

No [censored], learn something every day.

Most early Ford Broncos came with 3:50 from the factory. That Blazer will probably burn up the torque converter with any tire larger than 33”.

Chalet is correct… 3:08, 3:42, 3:73 or 4:11 are the square body truck rear ends.

Just to say, an axle swap to the desired ratio is a good bit cheaper than paying to swap gears in the axles.

Charlie

After further research, Charlie is correct. Chevy does make 3.55s but not in that axle. Maybe mine had 3.42s.

If you're sticking with 37's and need new gears might as well swap axles and upgrade to 3/4 ton. If somebody has already put in lower gears like maybe 4:56 then run it it til it breaks, might last forever - who knows.

Charlie is right - axle swap is cheaper than a rebuild if you can find a good used set with the ration you want, I haven't shopped them in a while. Last time I did the 3/4 swap, This time I'm happy with the 3.73 12 bolt and when I get everything else done plan on getting it rebuilt with new shafts, gears, Detroit locker maybe.....