DaveL82

You had pics a while back showing the beginning of installing a C4 rear in an 80 to 82 C3. I have an 80 and have toying with the idea of the Gulstrand 5 link or a C4 swap.

Plan is to add 17 x 10 wheels and flares to the car along with the suspension upgrade.

- What was the measurement from hub flange to hub flange on the C4 rear (width)?
- Did the C4 rear mount into the stock 80 to 82 frame ears?
- do you think this is aworkable solution?

Dave

Schmucker

He said he couldn't run as wide of a wheel as he wanted. I'd suggest moving the frame rails in a few inches (or replace that section with laddered chrome moly tubing to narrow it up but not have to change anything else) if you have the body off.

VegasJen

dave, i'm no marck here and maybe he'll check in soon since it's late morning over there about now. anyway, from what i know between the two and what i remember when having mine out, it *should* hang from the frame mounting ears. then the only issue will be how you mount that front point. fabbing either an ear to mount it like the original one or installing a late model tranny and modified torque arm. either way should work for you.
if your putting flares on the car, i don't see a reason why you can't put 17x10 in there. i would suggest fabbing different trailing arms to locate the bearings further in the wheel to reduce the side loading as long as your going to that much trouble. i'm interested in what you come up with. i'm contemplating a significant rear suspension redesign and looking for something someone else has already tested.

Twin_Turbo

The C4 batwing is a tad narrower than the C4 one so you need to mod the frame ears and reposition both mounbting holes about 1/2 an inch inward. The front mount can easily be made from a p[re 80 C3 front diff mount, the plate to bolt to the torque arm pad is pretty simple. A torque arm won't fit, our tranny tunnel is way too small for that.

The problem with the C4 suspension is that the 1/2 shafts are a good bit longer and this makes the wheels stick out. You could use the C3 1/2 shafts but you'd need custom struts, or maybe get 82 F45 struts. Maybe those will fit (they are aluminium too), the mounting ears on the diff for the C4 are similar in bolt pattern to the 1 piece bracket on the C3, they're all even interchangeable (C4 has 2 seperate ears on the sides).

Combining the idea of the C4 suspension and the 5 link that lohkay made I was thinking about the following.

Use a C4 Dana 44 (strength) and C4 hubs (light -> unsprung weight). They have all the mounting points needed for the 5 link (2 front mounts for the "dogbones", one lower camber strut mount and one rear toe strut mount), add a mount on the top and you'll have a nice 6 link. Use C3 1/2 shafts and custom struts so that the wheels don't stick out a lot.

The wheels sticking out isn't that much of a problem if you add flares but i have 12" wide rear rims and I can't imagine 6" or so flares looking good at all.

This is how much the wheels stick out:

compared to stock:


Marck

spikezz4

We used both the complete front and rear suspension from an 85 Corvette for our conversion. The 85-88 Corvettes front suspension is 3" less wide than the rear, resulting in the correct specs to run 17x91/2 rims up front. In the rear, we had to reduce the half shafts and strut lengths about 1 5/8" per side to get the wheels inside the fenders. Lots of engineering and measuring, and not for the faint of heart.
Spike

Twin_Turbo

do you have pics?

DaveL82

This is beginning to sound more reasonable. I want to run wheels that fit corectly in the flares and with the correct offset to reduce stress on the bearings.

The C4 spindles require wheels a lot more backspacing so if I get wheels that match the C4 spindle assy, the C4 strut rods and half shaft may work out correct under the flares.

No I need to check pricing of a used C4 diff in the Texas area.

Dave