Will 78 Camaro chassis work with 57

[LEE T]

How much drop on that blue nomad, front and rear?

[chevynut]

Lee, the blue Nomad is dropped 3" in front and 2" in the rear. That's our standard configuration. That's only the suspension drop, and tires can drop it even further if they're smaller than the 28.3" stockers. With a 26" tire the frame is about 4" off the ground at the front of the door where it kicks up which is about as low as I recommend going. Here's pics of it finished:

[rockytopper R.I.P 5-13-2017]

Are stockers really 28.3? I thought more like 27?

[chevynut]

Stock tires on 55-56 were 670-15. The LOADED rolling radius was specified at 13.4" (per GM specs) which makes them 26.8" loaded. I think the unloaded radius is at least 1/2" larger. Somewhere I found the 28.3" dimension at one time.

[markm]

Upgrade cost to stock depends a lot on who you are, I spent about half the 2700 quoted above on Steering and brake upgrades. Yes I have a 500 PS box, ft. disk, Ft. & Rr. sway bars.

[chevynut]

I spent about half the 2700 quoted above on Steering and brake upgrades. Yes I have a 500 PS box, ft. disk, Ft. & Rr. sway bars.

When, in 1970?

Based on Summit Racing's prices the CPP 5000 power steering box is $420 alone. Upper a-arms are $360 from CPP and lowers are $780 from Heidt's. A CPP dropped spindle kit with disc brakes is $700. Hotchkiss swaybar kits are $300 each. That's $2860 plus shipping.

Sure you can buy inferior parts for less, if that's what you want. And you might argue that you don't need the lower a-arms.

Now add the longer upper balljoints that Rocky recommends to correct the suspension problems for $160 a pair and you're over $3000. And you still end up with a suspension that's inferior to a C4 setup.

[rockytopper R.I.P 5-13-2017]

Drop spindles are junk I don't really understand your or anyone else's reason to keep using them. The result you get is this.

" I've known guys to pay $5-6K on bolt-on stuff and still not get what they wanted or expected. " as you stated above.

[markm]

I do not run dropped spindles. Nor did I buy bunch of cheap parts, my rotors are low mileage 72 Monte Carlo.

[chevynut]

Drop spindles are junk I don't really understand your or anyone else's reason to keep using them.

Because they're the best way to drop a car 2". Dropped springs reduce suspension travel and screw up the suspension geometry. The lower a-arms and steering rod ends on a tri5 or just about any car are DESIGNED to be level at ride height. Dropped spindles maintain that geometry. If the a-arms are angled so the lower balljoint is 2" higher at ride height any compression or extension of the suspension causes the lower balljoint to move in and out, scrubbing the tire. To me that's screwed up. Dropped spindles maintain the designed geometry. A taller spindle would be better and I wonder why nobody offers one.

The other thing that happens is the roll center drops with the balljoint above the a-arm pivot, causing the car to want to roll more.

[chevynut]

Rocky, I have never disputed your claim that a taller balljoint in the upper a-arm will make the stock suspension work better. If you raise the balljoint enough it moves the instant center from the outside of the vehicle to the opposite side. Anytime you have an instant center outside the vehicle (on the same side) the roll center will be below ground, which is bad as it will cause the car to roll more.

What I have a dispute with you about is the effects of dropped springs versus dropped spindles.

The stock suspension is designed to put the lower a-arm level on most cars. This is to minimize the side to side movement of the lower balljoint. When you add the taller balljoints, the instant center will be NO LOWER than the lower balljoint centerline, inboard of the a-arms or on the opposite side of the car. When a line is drawn to the tire contact patch, it will ALWAYS result in a roll center that is above ground. The taller the spindle, the more camber gain because the upper a-arm angle is increased. It also raises the roll center.

Now let's look at the situation with 2"dropped spindles. The lower balljoints are 2" lower to the ground, but so is the CG of the car so the distance from the CG to the roll center doesn't change. The contact patch doesn't move.

When you add 2"dropped springs, you've raised the lower balljoints 2" ABOVE the inner pivot. Now the lines drawn through the lower balljoints and the pivots hit the ground at some point on the opposite side of the car. When you draw a line through the UPPER balljoint and pivot, it intersects the lower line at a lower point than if the lower a-arm was level. So you have lowered the roll center relative to the CG, even though the CG also moved downward.

With an increase in distance between the roll center and the CG the car wants to roll a lot and will need stiff springs to control it. With a smaller distance between the roll center CG the car doesn't want to roll as much and can use softer springs. For a nice ride, I prefer softer springs. So not only will the car ride better and smoother, it will handle better with dropped spindles instead of cut springs. And you have the option to increase the spring rate a little if you want to plant the tires better, but you don't need as high or a rate to control body roll.