Lowering a '69 leaf spring C10

[Tquillen]

I have looked for information on leaf setups on the 67-72 trucks, and how they compare to the later squarebody trucks, without a whole lot of success, so here is a question for those in the know:

I'm in the process of doing a mild (2"/2.5") drop on my LWB C10. This one has leafs instead of trailing arms. While looking at the prospects for doing a simple leaf shackle install, I noticed that there is not much room between the rear leaf spring eye and the bed floor crossmember that runs above it. In all, there is maybe 1.75-2" clearance. In order to achieve a 2.5" drop, my math says that I'm going to need to raise the rear spring eye mount around 4-5" or so, or drop both the front and rear spring eyes by 2.5". Is this correct? I can notch the bed floor crossmember if I need to, I'm just looking for the best way to get there from here. I am planning on doing some light (less than 5000 lb) towing, so I really would like to keep the leaf spring setup. I am also planning on installing airbag spring helpers/levelers for use while towing. If I do this, can I eliminate the bottom leaf to help drop it some? Will this hurt ride quality? When not towing, I'll use this truck as a driver. Not a drag truck, not a pro touring ride. So a nice, comfortable ride would be nice (I know leafs give up a little in this department).

Thoughts?

[Tquillen]

To add: This truck has four leaves only. No overload. Which compounds the issue, and makes some of the other advice I have seen/heard (eliminating the overload) not applicable.

[mitchell72]

I used some extended shackles from an online speed shop. It lowered the truck nicely (i can't specify numbers) but when i put the bed back on the ears rubbed the floor. You may need to trim the ears.

I would go this route because it is cheapest. Measure twice.

[Mike C]

Early Classic has shackles for the narrower 1 3/4" springs the 2 wheel drive 67-72 trucks have. But as you can see, 1 1/2" is about all you can get from a shackle.

I did a DJM flip on my 69 short step and it lowered the rear 7 1/4" which is exactly what I was looking for. If you want anything in between, the correct answer is to buy leaf springs with that much drop.

2 1/2" in the front would go good with a 4" in the rear. I did ECE spindles and disc conversion with 2" springs in the front for a 4 1/2"/7" drop on my truck and I am super pleased with how it all came out. But you are getting really close to the bumpstomps all the way around at that point.

[Tquillen]

Thanks for the suggestions. After sleeping on it, I think my plan is to do the front first (CPP modular 2" drop spindles), measure the wheel well heights, and then drop the rear accordingly. I want the truck to be fairly level, maybe a tick higher in the back. Right now , the rear is about 1/2" higher. I'm thinking that I'll end up with a drop spring in the back and add blocks back to get to my desired ride height, and use the blocks to fix any pinion angle irregularities that come up.

[Mike C]

I like the back up just a bit as well. Here is a pic of my truck with the 4.5" front 7" rear.

[Tquillen]

Great looking truck! That's a fair bit lower than what I want for my truck. Interestingly, my truck has 2.25 inch leaf springs.

[72MARIO]

2.25 is standard 1/2 and 3/4 ton width. Using a longer shackle on a wood floor tends to cause interference with the bed floor. years ago ECE had custom spring pack to lower the ride height. If I was to do it aging a trailing arm swap would be the route I go..

[Mike C]

Originally Posted by Tquillen

Great looking truck! That's a fair bit lower than what I want for my truck. Interestingly, my truck has 2.25 inch leaf springs.

Sorry. That's what I meant. I've been working on jeeps, especially earlier ones with the narrow springs.

Yes, 2.25" springs while 4x4, Longhorns, and newer trucks are 2.5". My bad.

I have CalTrac bars on mine for a future big block swap, and one of the great things about leafs is you have room for exhaust!

[gvnick]

You can also get some drop by relocating and flipping the front hangers. I did this on my truck. This combined with a shackle in the back can get you the drop you are looking for and keep your geometry right.

I have since gone to an aftermarket hanger (which I cant find online now), but this was much more drop than you are looking for anyways.

[Tquillen]

Originally Posted by gvnick

You can also get some drop by relocating and flipping the front hangers. I did this on my truck. This combined with a shackle in the back can get you the drop you are looking for and keep your geometry right.

I have since gone to an aftermarket hanger (which I cant find online now), but this was much more drop than you are looking for anyways.

I am interested to see how you did this. Pictures?

[gvnick]

No pics as they are already off the truck, bought some aftermarket hangers to go even lower. But its easy with some basic fab skill. Grind out the rivots, move the hangers up the desired amount and bolt them back in. I made a gusset for the top of my hangers because the top holes were above the frame rails.

In my opinion its the most proper way to lower your truck, and its the cheapest.

[Tquillen]

Ah, I understand now. I'm thinking of fabricating my own set of hangers. The ones I've seen don't do much for my confidence. I fully agree that taking the entire assembly straight up is most likely the best way to do what I want with the fewest compromises.

Odd, how building a racing suspension from scratch doesn't bother me a bit, but lowering a leaf spring truck gets my head in a twist, LOL!

Thanks for the input, fellas. Much appreciated.

TQ

[zosoppp]

ECE also has replacement 4" drop leaf springs for the rear leaf 1/2 tons.

Drop Rear Leaf Springs (Pair)
Click to View
For Classic Truck owners with rear leaf springs, we offer 4-inch Drop Leaf Spring Assemblies to lower your truck, as well. These brand new multi-leaf assemblies are made right here in the U.S.A., and come assembled and ready to install. Combine with our 1½-inch shackles for a 5½-inch rear slam.

PN #02-6772-4LF

[MDPotter]

Posting here for anyone else that is looking for info on lowering a leaf spring truck.

Mine is a 68 GMC C15 and it had the HD rear leaf setup - a total of 8 leafs. I bought the 4" drop leaves from Western Chassis (through Summit) and ended up with just over 3" of drop. All I can guess is that my factory springs had sagged a little bit over time. I was expecting more than 4" of drop because the leaf pack is so much slimmer than the HD leaf pack, but not the case. I could use more drop, maybe the flip kit is what I needed but it would require a c-notch in my opinion. I put the shocks back in the stock position and it's not too extreme. The measurement between top of the axle tube and the underside of the frame is 4.15", where I was 7.25" with the stock springs and shackles.

I have a set of small tires on this truck right now (26"), so keep that in mind. I cut 1 full coil off the factory front springs and probably dropped about 2".

Also, don't forget to order u-bolts because they do rot away over time, even in drier climates.

[BlueyC10]

Originally Posted by MDPotter

Posting here for anyone else that is looking for info on lowering a leaf spring truck.

Mine is a 68 GMC C15 and it had the HD rear leaf setup - a total of 8 leafs. I bought the 4" drop leaves from Western Chassis (through Summit) and ended up with just over 3" of drop. All I can guess is that my factory springs had sagged a little bit over time. I was expecting more than 4" of drop because the leaf pack is so much slimmer than the HD leaf pack, but not the case. I could use more drop, maybe the flip kit is what I needed but it would require a c-notch in my opinion. I put the shocks back in the stock position and it's not too extreme. The measurement between top of the axle tube and the underside of the frame is 4.15", where I was 7.25" with the stock springs and shackles.

I have a set of small tires on this truck right now (26"), so keep that in mind. I cut 1 full coil off the factory front springs and probably dropped about 2".

Also, don't forget to order u-bolts because they do rot away over time, even in drier climates.

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How wide are the leafs ?

[MDPotter]

Originally Posted by BlueyC10

How wide are the leafs ?

I sold the truck in 2023 but they should be 2.25" according to Summit Racing (seller of Western Chassis parts).