Front Suspension Conversion Options

[D-n-Tyke]

So I am trying to convert my 69 C20 over to 5 lug disc on the front. Really wanted to find a 73-87 complete front suspension and just swap the whole thing out. Unfortunately I am having a hard time finding one in San Diego (or anywhere within a reasonable distance) so thinking of going in a different direction. I am planning on going with drop spindles anyways so buying those isn't really an additional cost, same for springs. Now tubular control arms would just be a plus so buying those would be easy to justify (right). My question is, if I buy 73-87 control arms will they bolt up to my 69 crossmember. Additionally if I get 73-87 drop spindles what will I need to change to make them work? I believe the outter tierods have to be changed, but can I keep the inner tierods and crosslink/idler arm? Then ofcourse master cylinder, calipers, discs and bearings can come from autoparts store. Would this work? Am I missing anything else?

[Zachary17]

I Believe that the 73/87 Control arms can bolt up to the stock front crossmember but not sure.You can use 73/87.HD Spindles with your factory control arms but have to use 73/87 ball joints and outer tie rods and get a conversion sleeve for the tie rods.or you can do it The way I’m doing it on my 70 GMC use 73/87 spindles ball joints inner and outer tie rods center link idle arm and use the factory pitman arm.
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[LockDoc]

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You will find your answer in this thread....

http://67-72chevytrucks.com/vboard/s...d.php?t=444823

LockDoc

[D-n-Tyke]

Thanks for your reply guys. Appreciate it.

I have spent the last 4 hours reading thru the link LocDoc posted along with a ton of more searching thru the forum and am still a little confused on my best option. I also deep dived into CPP's website today and since I am planning on getting drop spindles anyways thought it might just be cost effective to try and buy one of their kits and be done with it (especially since I can not find a complete 73-87 front suspension her in San Diego).

SoI need to ask for advise on the best way to go with this.

I found CPP's Upgrade Spindle Wheel Brake Kit (P/N: 6370SWBK-5D) which comes with everything including both ball joints, inner and outer tie rod ends, tie-rod sleeve, calipers, rotors & bearings. Basically I would be able to rebuild my whole front end (minus a-arm bushings) with this kit. My only question is, will these ball joints fit in my C20 a-arms? ie are the arms the same between C10 and C20 and just the ball joints are different, or are the arms different too. Additionally would the tie rods provided in this kit work with my stock C20 cross-link or at the tappers different?

When I called CPP to ask what they thought the best way to do this they pointed me to their C20 modular drop spindle (P/N: 30106-HD2) which then I would also have to buy the caliper bracket (P/N: 6087DBK) and their brake kit (4CK-5). Going this way would bolt directly to the stock ball joint and tie rod so I wouldn't have any worries there, other then having to buy those separately to rebuild the front end (no big deal, just more money).

If both options will work with my C20 A-Arms and Cross link is there any big advantage of going one way or the other? The only one I can see is that the modular spindles narrow the track width while the standard spindles widen it slightly. I haven't selected my wheels yet so not sure if that is a big deal or not?

Plan for the truck (well actually Suburban) is to just cruise it, no hauling or toying.

[gmc684x4]

It widen the track width in relation to 70 and older trucks 71 and newer trucks will be the same track width .
In a way its a perception issue and will you use a 70 and newer diff which will be wider too then the old drum drum brake trucks

Are you looking just at adds or are you posting wtb adds and actually getting out there looking in pick a part kind of yards seen a few 67 72 and sb trucks on a California youtuber channel quit watching them over how much they break on there channel and lack of knowledge they pretend to have
Widen your search patterns a bit may open up a lot more options

From what I have seen cpp parts can be a hassle to make fit

[D-n-Tyke]

I have been looking in all the usual posting places and calling all the wrecking yards with no luck. I even started looking up towards LA and out towards Yuma but at some point the drive out ways the cost savings.

Already found a rear axle. Picked up a rearend out of 71 C10 the guy was going to full frame upgrade (missed getting the front end too by 20min).

That is the first I have heard about CPP. Very interesting. I will keep that in mind.

[gmc684x4]

Are you making your truck from a c20 to a c10 ?

I read never confirmed the you can use 73 up outer tie rods and 77 elcamino inner tierods with 67 70 center link.
I picked up a 95 g20 van I was going to use for spindles and a arms as they are a 73 87 set

I picked up a couple 71 72 front suspension since then

[D-n-Tyke]

Originally Posted by gmc684x4

Are you making your truck from a c20 to a c10 ?

I read never confirmed the you can use 73 up outer tie rods and 77 elcamino inner tierods with 67 70 center link.
I picked up a 95 g20 van I was going to use for spindles and a arms as they are a 73 87 set

I picked up a couple 71 72 front suspension since then

Yes, I am converting a 69 C20 to C10 (5 lug disc). Plan on installing a drop spindle at the same time.

[xs-cash]

Yrs ago I put the whole front suspension from a 76 1/2 ton into a 71 gmc 3/4 ton , like 16 bolts and it was done , took a couple hrs , quick and easy , the rear t jus cut all the brackets off the 1/2 ton and lined it up and welded the perches on. Easy !

[gmc684x4]

I am guessing a arms are the same 67 72 c10 c20 with different ball joints
The a arm shafts are the same part
I could measure up a 72 c10 ball joint against a 72 c20 ball joint this weekend I have a c10 front suspension I pulled apart this spring then found a nice complete c20 to build I have the old lower c20 ball joints I could compare to the c10 ones

[D-n-Tyke]

Originally Posted by gmc684x4

I am guessing a arms are the same 67 72 c10 c20 with different ball joints
The a arm shafts are the same part
I could measure up a 72 c10 ball joint against a 72 c20 ball joint this weekend I have a c10 front suspension I pulled apart this spring then found a nice complete c20 to build I have the old lower c20 ball joints I could compare to the c10 ones

Oh man if you could measure those ball joints that would be very helpful. I did some more research last night and am now thinking that a C10 ball joint will NOT fit in a C20 control arm, but your measurements would confirm or reject my findings.

[lolife99]

Originally Posted by D-n-Tyke

Oh man if you could measure those ball joints that would be very helpful. I did some more research last night and am now thinking that a C10 ball joint will NOT fit in a C20 control arm, but your measurements would confirm or reject my findings.

C10 upper ballpoints will work in the C20 UPPER A-arm
The C10 lower balljoint WILL NOT WORK in the c20 lower a-arm.
The c20 lower a-arm has a bigger hole in it.
You will need to source a c10 lower arm to work with a c10 lower balljoint.

[D-n-Tyke]

Originally Posted by lolife99

C10 upper ballpoints will work in the C20 UPPER A-arm
The C10 lower balljoint WILL NOT WORK in the c20 lower a-arm.
The c20 lower a-arm has a bigger hole in it.
You will need to source a c10 lower arm to work with a c10 lower balljoint.

Thanks for the confirmation.

[Mike Bradbury]

I am not sure it is relevant any more but when I did my conversion from Early Classics (permanently closed), they had a set of drop C10 spindles with C20 tapers bored in them. They fit right up. I still have all c20 parts except the spindles.

[lolife99]

Originally Posted by Mike Bradbury

I am not sure it is relevant any more but when I did my conversion from Early Classics (permanently closed), they had a set of drop C10 spindles with C20 tapers bored in them. They fit right up. I still have all c20 parts except the spindles.

You are correct, ECE sold a c20 conversion spindle that allowed the use of a stock c10 hd rotor and caliper for an easy c10 conversion.
I’m just not sure which year c20’s they fit.
I actually own a set of these spindles, but can’t remember if they are 71-72 or 73-87 application spindles.
I’m sure the 63-70 c20 trucks had different size ball joints compared to the later years.

[lolife99]

I found this ad online.
Quote:
I got these 3/4 to 1/2 ton drop spindles from ECE and used them to mock up a truck. they have grease on the spindle pins now and dust from being on the truck for 2 months. they have '0' miles on them and they will convert 71-72 and 73-87 3/4 ton C20 8 lug disc trucks to the 1/2 ton 5 or 6 lug rotor set up while providing a 2 1/2" drop. They are DIRECT BOLT ON, no ball joint or steering arm changes.

[lolife99]

Here’s the original tech article from ECE with pictures.
https://www.motortrend.com/how-to/04...4-58d69bff5ef7

[Accelo]

No withstanding the differences in track width and the complications adapting the ball joints, remember the -72 trucks have "A" arms with a solid connection. As in, what amounts to a greased thread that allows for the vertical movement of the "A" arms. In 1973 the trucks with to a rubberized insert like the cars of that era. You will get a quieter ride with the newer style "A" arms everything else being equal. Depending on your usage and goals it's something to be aware of.

[D-n-Tyke]

Originally Posted by Mike Bradbury

I am not sure it is relevant any more but when I did my conversion from Early Classics (permanently closed), they had a set of drop C10 spindles with C20 tapers bored in them. They fit right up. I still have all c20 parts except the spindles.

Thanks for the suggestion. I had seen those when I was looking but then saw, like you said, they closed shop. I think I missed them by like 6 months. Always my luck (see above about missing the complete 71 front suspension by 20 min when I bought my rear end).
I ultimately went with CPP's modular C20 drop spindle along with their 5-lug disc conversion. Have yet to install it, want to pull the front end apart, replace the ball joints etc and clean everything up before installing the new parts. Hoping to get to that in the next month or so. For some reason my wife thinks the I need to finsh the kitchen remodel before I start working in the burban again.

[1970 CST Short Wide]

I have a set of ECE 2 1/2 drop spindles For Sale that use the 73 up top ball joint that I removed from my 70. The reason for the 73 up ball joints is I have QA1 A Arms and coil overs. I went with the modular spindles for track width reasons.
I’d like to get $200 for them. Shipping isn’t cheap so pick up would be preferable.
Last set of spindles I shipped costed $65 FYI

[Mike Bradbury]

Well you could always do both at the same time. Just take the spare parts from the Burban work them into the kitchen remodel.

[Mike Bradbury]

Originally Posted by lolife99

I found this ad online.
Quote:
I got these 3/4 to 1/2 ton drop spindles from ECE and used them to mock up a truck. they have grease on the spindle pins now and dust from being on the truck for 2 months. they have '0' miles on them and they will convert 71-72 and 73-87 3/4 ton C20 8 lug disc trucks to the 1/2 ton 5 or 6 lug rotor set up while providing a 2 1/2" drop. They are DIRECT BOLT ON, no ball joint or steering arm changes.

Yup that is what I used, Really good system. I was bummed to learn that ECE folded.

[D-n-Tyke]

Originally Posted by Mike Bradbury

Well you could always do both at the same time. Just take the spare parts from the Burban work them into the kitchen remodel.

Man, I would do that in a heartbeat if I had those spare parts.