[capev86]

yes you can (and should) upgrade the rear springs on a stock height 1/2 ton panel or burb. my dad did that with his 72 burb back in the mid 80's when the original coils were sagged and we had (and still have) a '71 holiday 23 foot camper that weighs 6000 pounds loaded with an 800 pound tongue weight. turns out the standard 3/4 ton rear coils were optional equipment on all 1/2 ton trucks including blazers! with the soft 1/2 ton fronts the truck rode good and the stiffer rear coils gave it a nice rake and the aux overload springs never engaged after the upgrade. i bought a set of 3/4 ton HD option coils for the back end of my 72 burb 3/4 ton for the distant future when i'm rich and have a 40 foot toy hauler behind me! i would suggest you steer clear of those on a 1/2 ton axle......they are nearly 1 ton class springs and best for frequent heavy trailer towing. but i'd want the base 3/4 ton rear coils on anything other than a short bed that doesn't see any cargo. you will get a little rougher ride and a bit more bounce on rough roads but it is a great compromise and will help with rear body roll and keeping the front 1/2 ton spec will make things pretty smooth overall.....you had a great idea!!

rear coil spring weight ratings (per side) from my 72 burb dealer brochure:

1/2 ton: 1400lbs, 2000lbs

3/4 ton: 2000lbs, 2750lbs

oh yeah.......LMC has good prices on brand new coil springs if you don't find a good used set cheaper. they don't even list standard 1/2 ton rear coils....only lowering springs and variable rate springs. the vari-rate units tend not to be as nice as they sound (sag before they stiffen up). just compare the part number and you can see that the stock style 1/2 ton rear coils they carry are the 1/2 ton HD / standard 3/4 ton units.