Wanna slam that 63-98 C10/C1500? Lets talk about it!

[bluex]

Lowering your C10/C1500 (1963-1998)

So, you want to lower your truck? Got questions about how/why/what to buy? Hopefully this will help with your decisions. I will try to address most of the common questions/issues and give you a good idea of what to look for and anything that will trip you up. I know this is a squarebody forum but most of us have multiple projects and this information transfers across all these years. We will start at the front; I’ll break it into sections and try to go item by item.

FIRST OFF, In my opinion AVOID any and all of the prepackaged kits and all types/kinds of “drop shocks” I’ll explain more but that’s always the first question and will lead you to a compromise that will make you unhappy with some part of the kit or the ride quality.

Spindles:

Always start your drop here. Spindles help keep the factory ride quality, and alignment specs are easier to maintain. While they are slightly more involved on the install and cost more up front, it is the best option for the first part of the drop process.

There are 2 places that cast drop spindles, so regardless of whose name is on them, they pretty much come from the same place. Any of the bigger name companies are fine to purchase from. They all have a good track record, and all the standard spindles have the same clearance and install issues. There isn’t one that is noticeably better than another.

For 63-87 they come in 2.5” or 3”. It doesn’t really matter which one you use. If you want to keep 15” wheels I would do the 2.5” since it won’t require as much trimming to the a-arm. Anything 17” and over on wheel size should not require trimming. You will have to trim in this area for wheel clearance, it does not affect the strength of the arm at all. Leave the bump stop area alone for a static drop, the trimming you'll need to do will be on the edges out by the ball joint on both sides of the A-arm.

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All 63-72 spindles are setup for 1.25” rotors. If you want to build your own disc brake conversion you can get the spindles and then rotors/bearings/brakes for a 73+ (if you want 5 lug) the swap kits are generally about the same price as buying all the stuff on your own though. If you want to stay 6 lug those rotors are available but only for 1.25” spindles. So yes, if you want them on a 73+ they will work with the correct spindles for a 6 lug 2wd.

On 73-87 you can have 1” or 1.25” thick rotors. Generally, 73-80 are more commonly going to have 1.25” and 81+ will be 1”. However, you still need to measure before ordering the spindles because the trucks could have been ordered either way through the model years. From what I’ve seen there’s no rhyme or reason as to why one truck got “big” brakes and one didn’t. So, save yourself the hassle and measure them before you order. You don’t need a caliper to measure them just to know what spindle to use, a tape measure is fine, but measure the same way it shows here.

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Aside from the A-arm trimming the brake line will need bent to clear the spindle ear and the ball joint nut. This is easily done after everything is bolted up, you can take a large crescent wrench and bend it slightly until it has room around everything and while turning. I have also run across a few sets of spindles where the dust shield bolt holes are not tapped deep enough for the factory bolts. Watch that because if they bottom out before the shield is tight and you try to keep going, they will break off in there.

88-98 all C1500 spindles are 2” drop, and you also still have the option of 1” or 1.25” brakes. The 1” rotors are far less common in this generation though. 88-91 regular cabs were the only ones that could get 1” rotors. 92 and up everything was 1.25”. All extended cabs, Tahoe and Suburban are 1.25”

All the spindles for these trucks widen the front track width, except for the React spindle from AZProPerformance. This is a new(er) spindle and should be the go-to unless you’re on a serious budget. Any off the shelf cast wheel with a 245 or wider tire will need the fenders rolled for clearance (4” or more drop) unless you use the React spindle.

The brake line might need some bending here as well but there are no a-arm scrubbing issues on these trucks with 15” wheels. However, while the front end is apart do yourself a favor and remove the knockouts from the upper a-arm. The tool is cheap, but it can be done with a punch and a hammer. If you plan to lower more than 1 truck the tool is a good investment.

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Link to the tool:

https://a.co/d/ipbNTr6

There are a lot of other options for spindles now (63-87), I tried to stay just on stock style for this post. I have used a set of the new CPP X10 with the hub less rotors. That’s a nice setup and gets slightly bigger brakes. I haven’t been able to get a set, but I also like the looks of the Detroit Speed kit that utilizes a GMT900 hub, rotor and caliper. I am big believer in easy-to-get factory parts as I like to drive my trucks and I don’t want to be stranded somewhere because of a custom part that has gone bad.

 

[bluex]

Springs:

So, there is a ton of debate about this as well. I’ve done or experienced pretty much all the options at one time or another.

1” drop springs are usually a waste of time, your factory springs are 40+ years old, with a ton of miles on them and are pretty worn out. Almost every truck I’ve put 1” springs on either didn’t get lower or was raised up anywhere from ½-1” over the factory springs. I stay away from them unless you like doing the same job twice. This is my main gripe with the Belltech kits, you never get 4” drop in the front.

2” or 3” springs are fine to use to get the remainder of the front drop you want. Again, here they are mostly the same, so it doesn’t matter who you buy them from. From 63-87 the front springs are all the same.

Avoid 4” drop springs, they are too short, are extremely hard to align and will fall out of the spring pocket every time you jack up the truck.

If you’re on a budget or you want to try and see how it looks lower before you buy springs you can also cut 1 coil off the spring with a cut off wheel. Do not use a torch, and don’t heat them. Too much heat is what alters the spring rate and makes it ride like garbage. The cut off wheel will not put enough heat in the entire spring to cause that issue. You can put the spring in a bucket of water if you are worried about that. Don’t cut more than 1 coil off unless it’s just for a height test. There are a bunch of trucks out there riding around with 1 coil cut and its never much of an issue. More than that is too much, and you’ll have the same issues as the 4” spring.

For 88-98 trucks the knockout removal is required for a drop spring installation. If you don’t do it while you have it apart, the alignment shop will have to do it for you. Most of the time this is anywhere from $200-400 extra cost depending on the shop.

Shocks:

This will cause some raised eyebrows for sure but avoid drop shocks. They are not necessary with the drop spindle at all and the 2-3” spring doesn’t alter it enough to require it either. I use and recommend a KYB GR2 344068. This is a stock replacement shock for 63-87, and no extender is required or necessary. These are affordable, easy to get and provide a great ride. The lower a-arm bumpstop will hit the crossmember before these shocks bottom out. My truck is on air, and I run these shocks. My crossmember lays on the ground and the shocks still have travel left. Sure, it isn’t much, but they still are not bottomed out and I don’t use an extender.

Now if you must use a drop shock because you just don’t believe me, then the only ones you need to consider are the belltech street and performance (sliver ones) series. Any other drop shock will leave you unhappy with the ride quality. Yes, by any other I mean absolutely any of them, the Belltech nitro, Western chassis DS-2, DJM, etc et all. They are all awful, I’m just being honest and trying to save you some money.

For 88-98 I always recommend the Street & Performance setup for them as the front suspension design is slightly different and there isn’t as much shock travel from the factory. I also haven’t been able to do any long-term testing on one to see if the stock front shock would still have enough travel with a 4-5” front drop. I believe it would be ok as all the shock would see would be the 2-3” of spring difference but I don’t want to recommend it without knowing for sure it’s a good option. I know the belltech silver is a good shock for them though.

 

[bluex]

Alignment:

Factory alignment specs leave a lot to be desired and if you can find a good shop that will work with you it can be better. These are the specs I ask them for, you might have to pay more but it will be worth it in the end. If you’re looking for a good, sporty driving truck then this is what you want to shoot for.

Caster +5.0 left and right.

Camber -.75 to -1.0 Anything over -1 will start to wear the tires on the inside edges.

Toe 1/16” In

These specs are not what the computer will call for on an alignment machine and is why I say you need a good shop that will do what you are asking for and not what the computer tells them. The big chain lifetime alignment type stores are not going to do this. You need a local guy that’s been doing alignments for 40 years type of place or a good friend at a shop that can do it for you after hours. My suggestion is to find a good shop, take your daily there a few times and once they know you, they will be more open to doing this for you. You more than likely won’t get a warranty or any kind of guarantee with this alignment though.


Wheels/Tires:

Unless your spending $1000-2000 per wheel don’t stress over backspacing options. All the off the shelf cast wheels that you can get for $13-1500 per set are going to fit and there is usually only one option for the backspace. What you need to worry about more is the overall height and width of the tire you want to run. On the front you need stay generally around a 245 or 255 max on the width and with a 4” or 5” front drop around a 27-28” overall height. This would be like a 245/40/20 or a 255/35/20. On 81+ trucks you are probably going to have rubbing issues on the inner edge of the front wheel well and it will be pretty bad with drops over 4”. Shorter overall height tires can help this but keep in mind small sidewalls contribute to a stiff/harsh ride. One way to gain a little clearance is to swap to 73-80 inners. This will nearly eliminate the rubbing on a 4” drop and will make a 5” drop behave more like a 4” with stock inners. The other option is a set of Mild Slosh Tubz that will give you plenty of clearance and you can run a little taller tire as well if you’d like.


That pretty much wraps up the front suspension lowering wise, I will add a little here about a-arms and sway bars though.

 

[bluex]

A-Arms:

The 73-87 arms are pretty labor intensive to rebuild bushing wise. It’s a wash really if you want to do that or buy aftermarket arms if you are paying for the labor. I like the CPP tubular arms on a static drop truck for the value they provide. You get new Delrin bushings, new ball joints, they will eliminate the clearance issues with 15” wheels and offer some geometry improvements over stock arms. For new stock style arms you can get uppers from your LAP but as of right now (2022) LMC has the rights to the lower arm and that is the only place you can get them, if they happen to have them in stock. My guess is we have about 3 more years before whoever is making them for LMC will be allowed to offer them to other resellers.

If you’re going to keep your stock arms and your shooting for that 5” static drop, then I would recommend beefing them up a little in the area between the bushings as they are the lowest portion of the truck and will be the first thing to hit.

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88-98 I don’t have any experience with aftermarket arms yet. Most owners of these trucks at the moment are just wanting to do the job as quickly and cheaply as possible. Replacement stock arms are readily available so if it’s necessary you can get those pretty easily.

DROP A-ARMS:

Don’t buy these, as mentioned above the lower arm pivot is already the lowest point of the entire truck. Adding a drop arm only makes this worse as now the spring pocket/plate is now the lowest portion. If you are running 20s with a 40 series or lower tire then you will definitely have scrub line issues with a drop a-arm and a flat tire. There is nothing to gain with them that you cant get from a rebuilt stock or CPP standard height arm.

Sway bars:

If your truck didn’t come with one, it will benefit from one either before you lower it or after. There are tons of options here and they are all pretty good. If you are sticking with stock arms, then the stock 1 ton 1 1/8” bar with poly bushings is always a great option. The standard 1 1/16” bar is still good if you find one or have it already. Switching to a set of aftermarket arms will pretty much always require going with an end link style bar. CPP and Belltech offer good bars that work well with aftermarket arms.

 

[bluex]

Alright on to the rear suspension

Spoiler alert, the best thing you can do to get the best handling and ride out of your truck is to ditch the leaf springs ASAP! The 67-72 guys have us beat here as the trailing arm setup under most of those trucks is a great start for a truck that doesn’t want to be super low (an by that I mean laying frame at a show, it’s a great option for a 5-7” rear drop).

Don’t want to drop the money on a complete rear suspension setup? I can understand that, so here’s how to get a good ride from your leaf spring truck from 73-98 and those 67-72s unfortunate enough to have leaves.

Flip kits:

Yes, skip all the other nonsense parts and go right to the flip kit. Don’t mess with dropped leaves, shackles, or hangers. They will just cost you more in the long run once you remove them and go with a flip kit anyway.

Most of these are all basically the same, my current favorite would be the one from Tin Works Fabrication. When you buy a flip kit, ALWAYS get new U-Bolts, especially on the 88+ trucks! The lower spring plate design on them is bad to hold water/dirt/mud an they start to rust away. I have had many of them break as soon as you try to loosen the nut.

When you install the flip kit the hole in the flip kit bracket will be offset. You want the hole towards the front of the truck. This will move the axle back some, the purpose of that is to keep the driveshaft from bottoming out or binding up and to keep the wheels centered. Every truck is a little different and some have needed to be back on their own weight or have pressure applied to the rear suspension to get the driveshaft back in. This is just due to the arc the suspension/axle moves in and where it is at full droop. Once back on the ground it will have the necessary travel it needs to work as designed.

If your selected kit doesn’t come with a set of rear shock extensions, then you’ll need to pick up a set of those as well. Again, it doesn’t matter who’s they are just get the cheapest one you can find. Also install them before you do the flip kit, most of them might require some clearance to the leaf spring plate depending on the flip kit manufacturer. You also want these to help with some angle correction to keep the shocks at a good working angle while allowing you to use a longer shock.

 

[bluex]

C notch:

On 73-87 trucks with a flip kit, you don’t necessarily need a notch. If you just plan to cruise around in the truck and won’t be hauling or towing much it will be ok without it. On large dips, bridge approaches or potholes it might hit the frame a bit but nothing major. You will have to remove the factory bumpstop and its bracket and replace it with a low-profile urethane bumper.

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Edit: Suburban and K5s will require a notch with a flip. No way around it unless you don't mind bottoming out constantly.

If you want a C notch or plan to go lower than just the flip kit, then best notch I’ve used is again from Tin Works Fabrication. Mcgahuys also makes good ones. Just make sure you get one that wraps above and below the frame. I know it’s done a lot, but also don’t install one while the truck is on a 2 post lift. I personally like to pull the bed, put the truck on a good level floor and up on 6 jack stands. 2 in the front behind the bumper, 2 before the axle and 2 after. This keeps everything in line and supported while you cut the frame and install the notch. Welding it in after is up to you, it certainly doesn't hurt but I also don’t think its 100% necessary if you buy a good notch. Access to everything for the rear install in greatly improved with the bed off and make the job a lot easier. Its definitely worth the extra hour worth of work to pull the bed and you can clean an paint everything too!

88-98 guys, bad news for you here, you NEED a notch with the flip. I’ve seen guys get away without one, but they hit the frame a lot more than on the 73-87 trucks. I always include one in any truck I’ve lowered or kit I’ve sold for these years. Factory bumpstop and bracket removal is also required on these with a flip. If you don’t remove it, it will ride on it and your back will hate you!

Shackles

There are multiple options here. On 73-87 a drop shackle will require trimming the bed brace for clearance. Again, most of these are the same so it doesn't really matter which one you buy. All the drop ones are usually adjustable for 1-2”. The top hole in them will be for a 2” drop. You can add these to a flip kit for more drop, but a notch will be required on any year truck to combine the two.

Now say you wanted to drop your truck just 4” and my above advice of skipping a shackle/hanger combo has you confused. Here’s the answer to that, if that is what you’re looking for and you are 10,000% sure you’ll never want to go any lower then by all means do the shackle/hanger combo for your 4” drop. I can count on 1 hand the amount of trucks I’ve left at a 4” drop over the years. They always want to go lower so that is why I say avoid the headache of a hanger install. Instead, pair a LIFT SHACKLE with the flip kit to bring the rear back up to that 4” level and then its an easy swap back to the stock shackle when you come to your senses and realize the truck needs to be lower.

 

[bluex]

Hangers:

As I’ve said, skip them at all costs. They just aren’t worth the hassle of installation unless you know for sure you never want to go lower. You can do these with the bed on but it sucks, the gas tank usually has to come out, the rivets suck to remove they are just overall a huge PIA.

Shocks:

As on the front suspension I don’t recommend a drop shock here either. I use 344072 for 73-87 with the extenders. If you want a drop shock and you don’t want to use the extender, then the only one to consider is the Belltech Silver Street and Performance. 88+ you guys can use an upper and lower extension from Belltech to help and keep the stock rear shock. Most people just buy the set of street and performance shocks and run the rear with the lower extender. At that point you’re using it more for angle correction than for shock length.

Wheels/Tires:

The same as the front here, don’t stress over backspacing on the wheel, pretty much all these trucks can fit a 10-11” rear wheel. I like to stagger my tire sizes and run a 30-31” tall rear tire to help with highway rpms a little bit (smaller tires=higher rpms). That will give the truck a bit of rake so if you don’t like that then try to keep the overall height the same front to rear or keep it closer together. EX if you have a 27” front then go with a 28” rear.

NOTE: 67-72 stepside trucks are very different in this area as they are much tighter to fit and generally need to stay around a 8-9” rear wheel with a 255 tire. They just don’t have the space that the fleet side trucks do.


67-72 Trailing Arm trucks:

I like to start the drop on the rear of these trucks with a 1.5-2” block, I like the Aluminum CPP ones. Just like the front suspension keeping the spring as long as possible keeps the ride quality better. A 4” drop is my break point on these. A 3-4” drop can be all in the spring, but after that you need to start with the block and make the rest in the spring.

The same info about notches applies to these, at over 4” it is pretty much required though.

At a 4-5” drop you can get by with a stock length replacement adjustable panhard bar. CPP makes a decent one that is very affordable too. Over 5” or anything on air you need to go to a longer one that has more control over the axle in its travel. The No Limit Engineering one is nice and does a good job but it is also pricy.

For rear shocks on this style suspension again avoid all the drop shocks or any relocation kit that keeps the shocks in the stock location. This location is not the greatest at stock height solely due to the shock angle and lowering it just makes it that much worse. You’ll never get a decent ride out of these trucks with the shock in the stock location. They are also in the way of running the exhaust out the back, but honestly that’s usually out the window on these anyway. Tin Works Fab and No Limit engineering make the best relocators for this suspension. Again, it isn’t cheap but this is what you want for a good riding and handling truck. They get them out from under the truck, set them at the perfect working angle and with them wider out on the axle they also help with stability. Neither of these kits come with shocks, because depending on what drop you’re running changes the length. No limit gives you part numbers for Monroe based off the installed measurement between the mounting points. If you haven’t noticed I like KYBs so with some trial an error I found shocks for these kits that I (an everyone else) likes. 0-4” of drop you want 344085, over 4” of drop is 344426.

 

[Big Chip]

Excellent! Very nice post, thank you for all the time you spent on it.

 

[Lugnut]

This needs to be a sticky, This would have definitely saved me a few headaches when I did and redid mine till I got it right.

 

[TotalyHucked]

Awesome post, definitely needs to be a sticky. I've played around by trial and error to get where I'm at, it's great to have this thread for guys to get a good base knowledge before they start. I've got a mixed bag of parts too.

I can confirm about trimming the stock springs. He's absolutely right that you can go too far with the springs and not be able to align. When I bought the truck, it was already dropped ~4.5/6 with a 2.5" McGaughy's spindle, 1 coil cut off the stock springs and a flip kit in the rear. It rode good but it just sat too high, so when I rebuilt the front end (A-arms and all, they are a MF'r to do ), I kept trimming the springs ~1/4 coil at a time until I was happy with where the truck sat. I kinda knew I'd probably gone too far and now I can confirm that, I've completely worn out the inside edge of my tires in ~23k miles. Whoops lol. With stock everything, they just can't get the camber right at my height. I should've just ordered some 3" spindles instead to split the difference between them and the spring. But paired with the Belltech SP shocks mentioned above, it rides great. I did scrub like a SOB with the stock inner fenders so now I'm running a set of SloshTubz Mild AC inner fenders. Now I've got all kinds of clearance up front. I'll probably step up to a 9 or 10" wide wheel in the future with more tire.

I'm also running a Belltech flip/notch and generic 2" shackle in the rear with Belltech SPs, Western Chassis shock relocators and 315/35/20s on a 10.5" wide rear wheel. The truck has been at this height for over a year and 10k miles. For having no aftermarket arms/4-link/etc, this is about as good as it gets for ride.

 

[pnwnvrdn]

Very informative @bluex
Thanks for taking the time to post this...should steer some people in the right direction.

 

[bluex]

Awesome post, definitely needs to be a sticky. I've played around by trial and error to get where I'm at, it's great to have this thread for guys to get a good base knowledge before they start. I've got a mixed bag of parts too.

I can confirm about trimming the stock springs. He's absolutely right that you can go too far with the springs and not be able to align. When I bought the truck, it was already dropped ~4.5/6 with a 2.5" McGaughy's spindle, 1 coil cut off the stock springs and a flip kit in the rear. It rode good but it just sat too high, so when I rebuilt the front end (A-arms and all, they are a MF'r to do ), I kept trimming the springs ~1/4 coil at a time until I was happy with where the truck sat. I kinda knew I'd probably gone too far and now I can confirm that, I've completely worn out the inside edge of my tires in ~23k miles. Whoops lol. With stock everything, they just can't get the camber right at my height. I should've just ordered some 3" spindles instead to split the difference between them and the spring. But paired with the Belltech SP shocks mentioned above, it rides great. I did scrub like a SOB with the stock inner fenders so now I'm running a set of SloshTubz Mild AC inner fenders. Now I've got all kinds of clearance up front. I'll probably step up to a 9 or 10" wide wheel in the future with more tire.

Moog offers offset upper a-arm shafts that add 1* of camber iirc. I used them when I was still on stock arms to help avoid a huge stack of shims so I wouldn't worry about them falling out. I'm sure you probably don't want to go through the hassle of installing them now but if you wanted to they would definitely help. Do you know where you camber is at now. You can get it really close with digital angle finder an board across the wheel face...

It could also be your toe, I thought I had a camber issue because i had inside edge wear too. I expected it because it's bagged but it was actually my toe that was way out. The camber was actually positive some at ride height. It was weird because it drove straight an didn't pull at all.

 

[Grit dog]

Great comprehensive informative posts. Thank you!

 

[TotalyHucked]

Moog offers offset upper a-arm shafts that add 1* of camber iirc. I used them when I was still on stock arms to help avoid a huge stack of shims so I wouldn't worry about them falling out. I'm sure you probably don't want to go through the hassle of installing them now but if you wanted to they would definitely help. Do you know where you camber is at now. You can get it really close with digital angle finder an board across the wheel face...

It could also be your toe, I thought I had a camber issue because i had inside edge wear too. I expected it because it's bagged but it was actually my toe that was way out. The camber was actually positive some at ride height. It was weird because it drove straight an didn't pull at all.

Yeah, I didn't find out about those shafts until after I'd rebuilt them and I am definitely not doing that again haha. I'm saving up for the QA1 full setup so these just need to last me another couple years.

Granted, it got aligned 23k miles ago when I put the 20s on and hasn't been touched since, so it's definitely possible it got knocked out. Could be toe or camber at this point (or both). IIRC, I told them to put as much caster as they could get in it and keep the camber around 1*. I think it ended up being around 1.5* of camber, which would be fine if I didn't do so much highway driving. All of my Mustangs in the past, I've had them set at 2-2.5* of camber and always had good tire wear, but I always cornered very aggressively, went on lots of mountain runs and generally drove it like I was on a road course. Hardly ever did highway trips though and highway trips are 80% of what I do with this truck.

I do remember they suggested getting the longer studs so they could put more shims in but I didn't want to, that's alot of leverage on there.

 

[Scott91370]

Nevermind. I was looking at the +- amount.