heavy?
 

My 72 has two sets of coil springs, small ones on the axle, large on the arms and a single leaf spring on each side of the axle. Is this considered a heavy half and did they make alot of these

Re: heavy?
 

What you have there are the 'factory overload springs'
Is the SPID still present in your glovebox? ....if so, post a pic up and that option should be listed there.
Also, check your GVW plate in your door. If your truck is a 'heavy 1/2' ton (for that year) then your plate should saw 5400lbs maximum instead of the typical 5000 lbs.
Normally the heavy 1/2 tons have the heavy rear spring, heavy front springs and heavier tires on them.

All Good
Coley

Re: heavy?
 

Those half leaf springs are a great thing to have since they can be removed with just one bolt each. My truck is a regular half ton and I've lowered it just a bit so it has softer springs than original. However, I do use it for hauling and towing and even a modest trailer tongue weight can drop the rear and raise the nose, not a good deal for secure towing. So, I found a set of the aux half leaves and brackets in a junk yard, got 'em for $25! For regular driving and light hauling I leave the leaves off and the truck rides nicer, not so "truck like". When I plan to haul a serious load or tow, I reinstall the half leaves and it is perfectly set up for those more heavy duty tasks. Best of both worlds! Takes less than 10 minutes to swap those extra springs in or out.

Re: heavy?
 

The factory auxiliary spring option includes only the 2 cantilever leaf springs. The coil springs above the axle must have been added by a previous owner.

Re: heavy?
 

My '67 has the leaf overloads, and they're adjusted maybe 3"? away from unladen right height. I've only noted it obviously getting down onto them once, otherwise I've never felt them engaging and causing undue stiffness. Definitely nice to have! I'd be tempted to say the smaller coil springs are an add-on, too.

Re: heavy?
 

Mine is lowered just enough that they are engaged just a touch at unladen height so they are used at all times in my instance when they are in. Thus why I take them in and out. Depending on how any given truck is set up your needs could vary. With them in and no load in or on the truck, it rides very stiff in back.

Re: heavy?
 

My 70 C10 has the big springs and also the small springs on the axle but no leaves. I always wondered what that was about