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Discussion Starter #1
Have just upgraded my 61 to LS1 power and 92 C4 rearend.Rear has coilovers at 375lb/in and adjust shocks on hardest setting but still rear bounces on rough road surfaces.Any advice appreciated.
 

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Discussion Starter #3
61 withC4 rearend,what spring rate?

Thanx snipcod,my only reply for what use it is,but thanx the same,kev.
 

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Discussion Starter #5
spring rates C1 with C4 rearend

Trouble is my C1 is not very C1 in the running gear dept.I'll get there in the end though!
 

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I would really like to see a pic of that C4 rear end in the C1. I'm used to restoring C1s to factory. Would like to see something different on these old dogs for a change. My email is [email protected]

Regards
KenH
 

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I have a C4 rear end in a C1 with normal leaf spring. I fitted the same spring that Rich Lagasse has in the front and back. It is a softer spring than the C4 original because the C1 is a lighter car. I think the spring rate may be as low as 300 pounds.

I also fitted a lighter spring in the front but it is still very harsh so I am investigating the spring and the gas shocks. It may be the shockabsorber valve rating causing the problem.
 

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It might be that the spring rate is too high and not letting the rear end move up and down. I have an old hot rod with coil overs and have 160# on it
 

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Have just upgraded my 61 to LS1 power and 92 C4 rearend.Rear has coilovers at 375lb/in and adjust shocks on hardest setting but still rear bounces on rough road surfaces.Any advice appreciated.
How easily did you get this to fit? I am about to tear down my wife's 61 to do a remodsteration and am trying to decide whether to use the orginal rear end or upgrade to a newer live rear end.
 

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Discussion Starter #10
How easy is it to fit a C4 Rearend into a C1 depends alot on your experience in the workshop.I wouldn't recommend if you havn't got workshop facilaties to hand but if you have then it's no real problem.I did it with the body on but a car lift is essential.The C1 frame rails are exactly the right width,so study the C4 rear,take many measurements,double check everything and go for it.Only a small amount of cutting of redundant brackets and spring hangers required.I welded a 2in sq steel crossmember in to take C4 diff mounts and coil mounts.All I can say is that it was well worth the hassle.
 

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I am doing a '54 with '86 rear. 300# sounds about right. I will have the axle shafts parallel to the floor when the car is sitting fully loaded. Is your rear stabilizer bar installed?
 

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Discussion Starter #13
Yes I installed the standard stabilizer bar.I did away with the standard C4 diff torque arm(that ally member that ties the diff to the chassis that runs alongside the propshaft),and simply bracketed off my crossmember holding the batwing to the frame.I used a stiff rubber bush to mount this.
I have also decided that the bouncy ride over some road undulations is not the suspension at all but the antequated seat springs,so a seat rebuild with modern foam construction is next on the agenda.It's also very important to get the suspension upper and lower control arms attached to the frame at the correct angles.I took photos of C4 with rear wheel removed and worked it out from there.There was also a good detail posted on one of the Forums
which gave dimensions etc,cant remeber which right now but could find it if you cannot.Kev.
 

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You say you did the conversion with the body on!! Wow, that’s great. I want to replace the rear with a C4 rear and have been going over in my head what I need. Did you take any pictures of what you did? I know I can figure it out, but seeing how somebody else did it, can help me see what I need to do. Also, did you get any additional room for wider tires by doing away with the leaf springs, or did the track arms take up that room?

Dave
 

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I apologise for not commenting earlier. It is my opinion that eliminating the torque arm may result in a changing pinion angle during acceleration/deceleration which will definitely produce a "choppy" ride. NEWMANCARCREATIONS.com has a torque arm assembly which is engineered to bolt directly to a C-1 frame. Since you are in the UK, they may be willing to sell it separately.
 

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I would really like to see a pic of that C4 rear end in the C1. I'm used to restoring C1s to factory. Would like to see something different on these old dogs for a change. My email is [email protected]

Regards
KenH
I did a C4 suspension conversion on a '62 about 6 years ago. Mine used the front and rear C4 suspension and was based on the Newman conversion. You can see the complete build at: www.carols62.com. If any of you are serious about doing this, I have some pictures of the rear end with enough dimensions to give you a good start. Drop me an email and I will send them to you.

Charles
 

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Discussion Starter #18
61 with C1 rearend,what spring rate?

Hi,seems my problem was not spring rate or removal of torque arm(this was replaced with a rubber mount direct to new crossmember above diff from which I've mounted coilovers) but too higher setting of adjustable shocks.Lowered setting and suspension now acts as it should and not just bouncing on tyres.I was getting this bouncing effect and thought it must have been too softer suspension and in fact it was too hard!
Thanks,Kev.
 
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