What to look for on used C4 suspension??
 

I am a C1/C2 guy, NOT a C4. So,can someone tell me what to look for on C4 suspensions? I am referring to the takeoffs I could use on a restomod. I would use either a tube or Dawson frame. I would probably want the Dana 44 or can a 36 handle an LS2 power? Visually, what is the obvious difference in a Dana 44 and 36? Are some years better than others? If so how does one determine years. Date coded? Where to find? I have been watching ebay and other sites. Thanks for your time. DG:thumbs:

The Dana 36 can’t handle the LS2! Use the 44, it’s a better design.

The main difference is a 44 has a stronger rear cover designed to put pressure on the rear end caps. (Inside the cover there are two pads cast in it that sit on top of the carrier caps). The 36 won’t have these and under hard takeoff can blow out the side of the carrier (pictures of a blow carrier upon request).

Dick,

C4 rearends came in two distinct widths. The pre-88 rear ends are about 2" narrower than the post-87 rears because of the ABS reluctor rings. The pre-88 rears also used drum emergency brakes like earlier cars did, but the post-87 cars used a caliper with the E-brake incorporated in the caliper. Sometimes, the early rears can make for a better selection of rear wheels, but both will fit in a C1 without having to section the halfshafts and struts. C2 Cars will require narrowing.

Either one will serve you well, and a D44 is a better choice for a LS2, but a 36 will live behind an automatic if you don't widen the quarters for huge rubber. The rear tires become the safety valve for all that power. You will find that a LS2 can pretty much smoke the tires at will, and as long as you don't do anything to dramatically increase traction, then the 36 will do fine. If you are going with a manual trans, the D44 is almost a must. The shock loading from the Clutch being dropped, will result in a shorter life for a 36. There is a much better chance of finding a performance gear already in a 44 than a 36. I believe the deepest gear that the factory put in a 36 was a 3.08, and even those are hard to find. Most 36 rears had a 2.92 rear gear, so a switch will be in order for a hot rod. I used 3.45 gears in both my 36 in my 59 and in the 44 in my 65, and I think that is about the ideal rear gear for a modern overdrive trans. With a 3.06 first gear, it gives about the same final dive ratio in first gear as a muncie with 4.88 gears, without sacrificing economy on the highway. In overdrive, it will be about the same as a Muncie with 2.27 gears! Any deeper gears will just be wasted due to the afore mentioned traction problems. My 36 had to have new gears, while my 44 came with 3.45 gears in it, so I did not have to shell out the bucks for new gears. Plan on pulling the rear apart and replacing, seals and clutch plates, and the rear will is very simple to rebuild. If the bearings are good, you wll not even need to setup the pinion depth or pre-load or the carrier bearing pre-load. Just keep track of the original shims and the locations of each set, and you can just put it back together. Go ahead an replace the Torrington bearings on the side of the case that the halfshaft yokes turn in. They are cheap insurance. The other bearings should be fine, but inspect them for any brinnelling or damage.

Expect to pay about $700-$800 for a 36 if you shop around, and a 44 will seldom bring any less than $1200, and can bring over $1500, even with a lot of shopping around. If you can find a 44 with the gears you want, you can save several hundred dollars by not having to replace gears and bearings, as well as having to setup the entire rear again.

Billy can give you help on how to trim down a stock spring to lower the spring rate so you don't have to buy a new lighter spring. I believe all his rolling chassis still use trimmed stock springs.


Regards, John McGraw


Regards, John McGraw

Below is a picture that shows the visual difference between the Dana 36 and 44. Main thing I look for is the two rear cover bolts on top of the batwing on the 44. The ones I have seen have the rear gear ratio and a date code stamped in the bottom of the differential case. Dana 44's are going for about $1800 in my area.

The early C4 front suspensions had an aluminum plate that mounted on top of the lower A-arm (may have been '84 only, not sure). The shock was mounted to this plate - kind of a mickey mouse setup. On the later ones, the shock bolted directly to the A-arm. Also when buying a front suspension, make sure the two vertical support pieces on the crossmember are nice and straight. The upper A-arms bolt to these supports and they are often bent if the car has sustained front end damage.

As you probably know, the batwing has to be modified for use on Billy Dawson's frame and the lower shock mount must be modified also. Unless you are bound and determined to do it yourself, you might be well advised to let Billy do it for you.

http://www.carols62.com/dana44.jpg

Only 2 different lower control arms were made for the C4 series. 1984 - 1987 control arm shock mounts bolted to a cross bracket along with the sway bar mounts. 88-96 sway bar connection and shock mount was cast into the LC arm. Only reason was for production cost & fewer parts to assemble. Not necessarily a stronger or better design.

To all that replied. Thanks for the information and pictures. DG