20 to 10 series top arms?
 

Its been a while, but the old crazy man is playing with the longhorn again! The camber will not come on right, due to the 3/4 ton top arms....am looking @ Ride tech top arms (1/2 ton). I understand, that the 10-30 series cross members are pretty much the same, but have to ask about the studs, that mount the top cross shaft for the A-arm? To give a little info, she has 71 lower arms, 75 spindles/ball joints /69/3/4 ton top arms & shafts. My big ?, is will the top studs accept the 1/2 ton cross shaft, or do I need to replace the top studs or mounts? Need help......Longhorn:chevy:

Re: 20 to 10 series top arms?
 

Never mind guys.....I have it figured;) the 3/4 ton takes a 9/16 stud, versus the 7/16 1/2 ton stud. The 1/2 ton arms will not fit.....time to talk with my machinist! crazyL:smoke:

Re: 20 to 10 series top arms?
 

Upper a-arms are the same length between C20 & C10. No camber gain to be had just going to the C10 part. RideTechs stuff is adjustable for offset (Camber) & uses different 'slugs' for Caster.

Moog makes/made an offset upper shaft (k6184) for the stock 73-87 year arms.

Re: 20 to 10 series top arms?
 

Thanks for the reply Scoti....I had hoped that you & Capt fab would ,chime in:smoke: The old truck is running one ring off a stock coil, with the 1st inch heated/flattend, to mimic the stock coil, My guess is about a 2 1/2 drop. She has 1 1/2 inch body drop(us old guys call it channeled). With the drop, the old truck does not have many shims to remove, & is about 2 degrees positive on the camber. I am not looking at more drop......love the stance, just want to make the alingment come on;) Thanks again............longhorn:chevy:

Re: 20 to 10 series top arms?
 

The RTech upper arms utilize the same approach for the increased camber (the shaft is machined more on one side vs. the other) to get an agressive Camber spec. The offset Moog arm does basically the same thing but they're only made for the later bushing style a-arm.

Target a minimum of NEG .5 Camber. There won't be any difference in tire wear @ that setting but corner grip will be better.

Do the Caster mod w/the lower arms as well. it's easy to get 5-6° POS Caster.

Re: 20 to 10 series top arms?
 

The upper a arms are the same but in my experience the 3/4 ton upper shaft is thicker pushing the top of the wheel out giving you the positive camber.

You could.possibly machine the upper control arm shaft thinner at the mounting points.

Re: 20 to 10 series top arms?
 

Thanks again to all .....I had thought about moving the lower arm forward. I have a drill press, & can do that mod:chevy: On the top shaft,do you guys have any thoughts on how much material needs to be shaved ,to give 2/3 degrees ,to get me to that .5 negative on the Camber? Thanks again to all you good guys:smoke: Longhorn

Re: 20 to 10 series top arms?
 

Hhmm..... Guess I would measure the difference between a 3/4 shaft & compare it to a 1/2 (and possibly RideTechs). If they're smaller OD, cut to that dimension.

Re: 20 to 10 series top arms?
 

Just installed these with my 70 cross member. Problem is earlier trucks used a round concave washer behind the control arm shaft that matches the convex area around the studs for caster adjustment. 73 and up use a washer that is flat on the back side and curved on the control arm side to match the control arm. If you install both washers you have too much positive camber without any shims.

Re: 20 to 10 series top arms?
 

I recall grinding the convex/concave area until it was flat on one side of some shafts. I don't recall the parts combo used but remember doing it on the table/bench grinder @ work.

I'll look @ my stuff & see if I can jog the memory (I think it was on my dually).

Re: 20 to 10 series top arms?
 

That is where I am ;) But all of my parts came from a 69-71 truck. My spacers, came from those yrs, & the shims go into the back side of the spacer. I do understand that machining the cross shaft may be the best deal......might have to burn a number, & think about it:smoke: Many thanks for your thoughts...CL :chevy:

Re: 20 to 10 series top arms?
 

I may try that or just put the original shafts in. The 73+ shafts have one flat side that could be turned in to just use the earlier washers.

How low are you going? I haven't run into that issue. Only bought these "camber correction" shafts because I got them cheap on marketplace. Just created more work for myself.

Re: 20 to 10 series top arms?
 

I like the drop/stance....2 1/2 on the spring, + 1 1/2 on the body drop.The way the old truck is set up, nothing drags the pavement!. The rear is a flip/relocate brackets, for about a 5 inch drop. With the 4 inch chop top, the top it is about shoulder height on this 5ft 9 old man @ the top.....I do not want lower, just want to bring it (square) with what I have. Longhorn:chevy:

Re: 20 to 10 series top arms?
 

I purchased a caster camber guage, & was able to pull the camber in to 1 degree positive, & the caster to 2 1/2 degrees positive.....should be within factory spec? It will take machine work to get to the custom/performance specs, but that will be over the winter. Thanks to all for replies, Longhorn:chevy:

Re: 20 to 10 series top arms?
 

You want NEG camber not POS for better 'driving'.

Re: 20 to 10 series top arms?
 

I do understand that Scotty....it should be about 1/2 degree negative , on the camber.....but will take machine work on the top shafts to get there. In my understanding, I am within factory specs? Let it run for the season....take it down over the winter & then play with caster/camber;) My understanding, is that 1/2 neg, to 1 1/2 degree pos is factory spec.....not perfomance spec, but will not kill the tires. Bring it back bud, I have much to learn about this;)longhorn

Re: 20 to 10 series top arms?
 

Gotcha. Yes, the + camber number you listed would be considered 'in spec'.

I recall the OE target was +0 to +1 camber. This is why I target the .5 NEG as my minimum. Given your limitation, it makes sense to align as best you can w/what you have.

Re: 20 to 10 series top arms?
 

Thanks again.....with a little help from a good bunch of brother truckers, she will rock;) Longhorn:chevy:

Re: 20 to 10 series top arms?
 

What series suspension are you running (10 or 20)?

Re: 20 to 10 series top arms?
 

I am running 10 series suspension.....she does have the 20 series top arms/shafts, & a pair of 71 (10 series) lower arms. The rest is 75 10 series, on the spindles, ball joints & outer tie rod ends. The springs are 10 series, with 1 ring off the bottom. I also fabbed shock relocators, trimmed the bump stops & left the steer stop on the lower arms. She also has a 30 series sway bar, with fabbed brackets to fit .IIRC , the bar was flipped upside down to fit. Thanks again.....longhorn:chevy:

Re: 20 to 10 series top arms?
 

I would try drilling out some early C10 upper shafts for the mounting studs to pass through. Wouldn't take much & you get the smaller diameter (thinner) shaft to help your targets.

Re: 20 to 10 series top arms?
 

Good idea Scoti......I will check that route out. I guess it is a matter of , the cost of parts vs the machine work? All the parts on my truck are fresh(within 6000 miles). Let us go :smoke: a number& kick back ;) longhorn

Re: 20 to 10 series top arms?
 

I don't recall the upsizing of the mounting hardware to be significant if @ all.

Having limited access to early C20's/30's (pre-73), I have been told they utilized 9/16" upper mounting studs but never had one to validate the info personally.

Most later disc brake 1/2 tons utilize 1/2" upper studs. HD trucks were 9/16".
Early pre-disc brake lower control arm U-bolts were 1/2". Post-72 disc brake are 9/16".

I just put calipers on the old/original upper shafts from my 64 as well as a pair of uppers I got from one of N2billets 67-70 builds. These are original shafts & they allow a 9/16" bolt to pass through. The old/original x-member from my 64 has 1/2" upper mounting studs. The post-72 pancaked x-member I have has 1/2" upper mounting studs.

The early shaft diameters are 15/16" & flat where the bolts pass through (no Concave shape). The later shaft I have is 7/8" @ the shaft & ~1" where the stud passes through (w/the Concave notch).

Point of all this is it's quite probable the C10 shafts fit what you have w/o drilling anything. I would check the dimensions for what you have & compare. There might be no gain or @ the minimum a possible 1/8" gain if one side is flat.