73-87 suspension swap ???

[coreyslude]

Just to make sure i have this right. The fifth part about using the existing crossmember, I would use the control arms, spindles, tie rods, everything from the 73-87 and nothing from the 1967 that i have but the actual crossmember? And any aftermarket parts i buy drop spindles etc would be the 73-87 stuff? Sorry to beat a dead horse just making sure.


67-70 truck with

73-87 Crossmember Not Yet Installed:
1) Your donor 73-87 crossmember came from the factory with disc brakes.
* This swap is almost a direct bolt in, with just a few holes to drill/elongate.

2) The preferred method is to use all of the 73-87 steering linkage:
* This includes the centerlink, inner and outer tie rods, idler arm and steering box. (A great way to gain P/S)

3) If you must use the 67-70 steering components, you will need to change the tie rods:
* The 67-70 inner and outer tie rods are a smaller diameter (5/8") vs. the 73-87 tie rods larger diameter (11/16").
* The 67-70 tie rods are also the opposite thread direction of the 73-87 tie rods.
* 67-70 inner is RH thread vs. 73-87 inner which is LH thread.
* 67-70 outer is LH thread vs. 73-87 outer which is RH thread.

3.1) So to connect the 73-87 spindle to the 67-70 steering centerlink you must use a:
* 67-70 outer tie rod (LH thread) in the inner location.
* connect that to a tie rod "conversion sleeve". (these are sold by many aftermarket suspension companies).
* use a 73-87 outer (RH thread) to connect to your 73-87 spindle.
* Again,... it's much simpler to use all of the 73-87 steering components.

4) Connecting the 73-87 rubber brake lines to the 67-70 steel lines, may require steel line fabrication, or brass "inverted flare" adapters.

5) You can also just swap all the components, from the a-arms out,... and leave your original 67-70 crossmember in place.
* This will require you to completly disassemble both the original 67-70 suspension and the 73-87 donor suspension.
* This is also a good time to clean, inspect, replace or rebuild any needed components.

[SCOTI]

Originally Posted by coreyslude

Just to make sure i have this right. The fifth part about using the existing crossmember, I would use the control arms, spindles, tie rods, everything from the 73-87 and nothing from the 1967 that i have but the actual crossmember? And any aftermarket parts i buy drop spindles etc would be the 73-87 stuff? Sorry to beat a dead horse just making sure.

Correct.

One difference between the old/newer parts will be the lower control arm u-bolts are slightly larger starting in 73. You can drill the x-member holes out & use the larger diameter u-bolts or re-use the smaller diameter ones. The larger u-bolts are the better choice, but it can be done w/the smaller ones.

[coreyslude]

Thanks that's what I was thinking just wanted to be sure before I started working on it.
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[SCOTI]

You can use the 73-87 or 71-72 brake line routing. Whichever you like better or is easier to do.

[MADMIKE]

Originally Posted by SCOTI

Correct.

One difference between the old/newer parts will be the lower control arm u-bolts are slightly larger starting in 73.

FWIW, on the '70 2500 GMC the U bolts from the '84 2500 Suburban fit the truck with no problem.

Is this a difference from C10 and C20?

[SCOTI]

Originally Posted by MADMIKE

FWIW, on the '70 2500 GMC the U bolts from the '84 2500 Suburban fit the truck with no problem.

Is this a difference from C10 and C20?

No. C10 to C20/30 u-bolts are the same size. The drum brake equipped trucks have the 1/2" dia u-bolts; disc equipped trucks have 9/16" u-bolts.

[peglegs]

if he uses the 73 + cradle what motor mounts are used 67 or 73+?

[SCOTI]

I would use the correct 'towers' for the frame rails. Locate them on the frame rail & enlarge or drill any holes required in the x-member.

[doublebeetx]

Many years ago before CPP kits and all were the rage, I found out for my 63, mid 70's ball joints were the same size and fit the 63 control arms. I left the stock control arms in place, replaced the ball joints, installed 3 inch dropped spindles, discs, and had to figure out the linkage and brakes. Worked like a charm.

[SCOTI]

Originally Posted by doublebeetx

Many years ago before CPP kits and all were the rage, I found out for my 63, mid 70's ball joints were the same size and fit the 63 control arms. I left the stock control arms in place, replaced the ball joints, installed 3 inch dropped spindles, discs, and had to figure out the linkage and brakes. Worked like a charm.

Exactly. I've been using post-73 disc stuff on pre-71 set-ups since the 80's.
X-members will interchange.
BJ's will interchange.
A-arms will interchange.
Brakes & brake lines will interchange.

There are several ways to do the swap based on each unique set of circumstances. This is the big reason I promote using a donor 73-80 truck for the swap. You get extra little things like line clips & such (backing plates etc...) & can use the old parts for core deposits where required. Much easier to use your local auto parts house vs. a 'classic parts' place that's in another state when it comes to warranty related issues as well.

[Devil Pup]

I actually just did this swap on my 69 C20 this weekend, I pulled a 75 C10 set up out of the junk yard. As Scoti says the core amounts are worth having the whole cross member for parts so i recommend that too. The whole cross member literally bolted in. I didn't "have" to enlarge/drill any holes. However to make things a bit easier i did decide to ream out two holes just for ease. Everything bolted right in, I have the full cross member in, Disc brakes, Power steering, Drop spindles, Air Bags etc. . . anyway the reason im even mentioning this is with the research you've done you are probably more then ready. Its a very simple swap. just takes a bit of time.

[el_bole]

SCOTI,
Lookin to buy '73 front(engine cradle) and rear axles for my '61....Will this swap be "painless" or is there a better way to go, different year?

Thanks

[SCOTI]

Hhmm.... 61-62's are slightly different when swapping out the torsion-bar stuff. I'll have to dig for info on that swap.

[el_bole]

Scotti,

Thanks for getting back to me....The only thing Im reading that I dont like about the '73 front axle is that its wider then on my '61.....about 3/4" (each side) if I remember correctly....

[Slammed50]

I am getting ready to make the swap as well into my '63. Just need to paint up my sandblasted parts. I am using the while cross member as well, only bad part is that the po pulled the gear box so I am sol on the core for that, other wise all is well. Picking up my new bushings and ball joint next week, I'll snap some pics for you of the process.
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[richards72chevy]

So that 3/4" would only be a problem if you were running a realy wide tire/rim combo?

[SCOTI]

Yep, or really low.

[el_bole]

Scotti,

Glad there are options!!! I just sealed a deal for a rolling 73' chassis, uhpolstered bench seat(sweet looking) and a 20 gallon fuel cell for $500!

I was waiting for your final response to my swap question but I wanted to jump on this deal. I'll make it work and check out that company

Thanks,
Roberto

[sduckworth13]

Here is a pic of my truck. I used a donor 1974 Chevy 1/2 ton suspension + front sway bar and rear end. I used the power booster, master cylinder and power steering gear box ( must notch frame or add the spacer bracket, or use a BFH to make the dimple so the gearbox will sit flush to the frame. A member on here sells them, his name is captainfab. I notched my frame for the steering gear box

[el_bole]

Great Info man!!! That set up looks sweet...Im there is a thread on here about

C-Notching but how did you do it? I like the looks of the stance on your GMC.

Just curious what did you mean by using a "spacer" to install the '74 rear end on your '67...

Thanks again....If you have any other pics of the install post em please!!! Gonna try to do this swap with out having to outsource the work LOL

Thanks again,
el_bole

P.S. By the way those rally wheels look great...thats the look Im going for on my '61.

[kieth]

Just a note, everyone talks about using the crossmember from a 73 to 87 pickup, just keep in mind that you can also use the front crossmember from 73 to 91, the burbs did not change until 1992....I used the 350tbi, 700r4, tilt, p/s, disc brakes, fuse panel , and wiring harness from a 1 owner 91 burb....spent $1100.00 on the wrecked 91. It worked well the only snag was the captaing fab power steering bracket moved the steering sector out about 1/2", had to shorten the tie rod so we could get the steering wheel centered and leave more adjusting room. This is not a major problem just thought I would point it out. Kieth
Kieth

[doublebeetx]

Hey Scoti, I'm going to the wrecking yard Wednesday while I'm off. I have 64 short stepside with 230. Will the steering arm of the 73-87 trucks fit on my manual steering box ? Was thinking I would try to pick up center link, sway bar, whatever I can find.
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[SCOTI]

Originally Posted by doublebeetx

Hey Scoti, I'm going to the wrecking yard Wednesday while I'm off. I have 64 short stepside with 230. Will the steering arm of the 73-87 trucks fit on my manual steering box ? Was thinking I would try to pick up center link, sway bar, whatever I can find.

I re-used the Pitman arm for each application since they weren't a 'wear' item. I replaced the idler arm for the specific application as well & just used the later stuff for the tie-rods & center/drag link.

It's a good idea to snag the sway-bar for sure....