[rolling money pits]

Since I’m daydreaming about doing this, was curious about a “hybrid” rear set up for these cars.

Research tells me the inherent, potential, issues with these. Specifically the crossmember area never being designed to carry the load of the springs. Body on frame and no access to a welder, never mind no knowledge of welding.

The E36 BMW rear suspension is set up sorta kinda like early Mustangs, the spring is located on top of the control arm and registers into the body, the shock is like an A body, mounts to the hub and a pocket farther up in the body, and is a well known weak point in that car. Being that way a true coilover is a no-go, as it would destroy the upper mounting area in no time flat.

Kits for them have spring in the factory location with the adjuster registered on the control arm, thus allowing ride height adjustment while the shock mounts like a factory one. Here’s an example

https://www.summitracing.com/parts/s...l/m3/year/1997

Could that same process be applied to the A-body’s? I cannot think of why not, but I’m no engineer. It would seem all that’s needed is the adjuster gizmo to fit the spring pads on the axle? I cannot say for sure on the above linked kit, but another I looked at the shock body was adjustable in length, so when putting on is set to stop travel before the arm drops low enough to jettison the spring, which wouldn’t be too fun.

[JLMounce]

The hybrid coil-over must have an upper spring perch to rest in. While the A-body does have that, the hybrid coil-overs that are on the market are nowhere near long enough to mount into the upper spring perch and attach to the shock mount. Beyond that, you'd need a hybrid with an eye mount and I've never seen that. I've only ever seen a t-bar mount because they are using a t-bar configuration as a retrofit for the original front shocks.

You could I guess fabricate some sort of t-bar mount in the factory lower spring perch on the axle, but you specifically state you don't necessarily have those skills. That means having somebody else do it. By the time you buy quality hybrid's at around $750.00 and have somebody fabricate something, you're likely going to be over the cost of a RideTech setup.

Because of how the rear-end is setup in the A-body, the rear coil-over conversions are among the easiest and most cost effective of all the muscle cars. https://www.ridetech.com/product/196...le-adjustable/

I always ask though, is the reason you want coil-overs simply because of ride height adjustment? A lot of people tend to say yes, but it comes from a place of not understanding what coil-overs are for, or how they work. Coil-overs by nature "can" adjust ride height, but the shocks they ride on, like every shock, is designed to work within a specific stroke range and the ride height must conform to that. The small amount of adjustment that you do get in height is more about corner weighting than it is about changing the way the car sits. In reality, most cars will only see about half an inch to a maximum of an inch of true ride height adjustability while keeping the shock happy. Can you go beyond this? Yes, however it usually comes with poor ride quality and early shock failure.

There is absolutely nothing wrong with a standard coil spring in your application. You can save yourself about 700 bucks by choosing a proper coil spring for the car at around the ride height you're after. You can always add rubber spring isolators if you need to go up a bit, or cut part of a coil if you need to go down a little bit. Use some of that $700.00 to buy a nice set of shocks, then put the remainder elsewhere in the car.

[ZeGermanHam]

Originally Posted by JLMounce

There is absolutely nothing wrong with a standard coil spring in your application. You can save yourself about 700 bucks by choosing a proper coil spring for the car at around the ride height you're after. You can always add rubber spring isolators if you need to go up a bit, or cut part of a coil if you need to go down a little bit. Use some of that $700.00 to buy a nice set of shocks, then put the remainder elsewhere in the car.

Words of wisdom. 95% or more of people who install coilovers get them set up how they like and then never touch them again. While that might be convenient up front, they make zero difference down the road if you don't need to readjust your suspension regularly to accommodate varying conditions/circumstances.

For a road car that will never see a track, a standard spring & shock setup is my preference. Simpler and cheaper. You just have to do your homework up front to select the right parts instead of using the adjustability of coilovers as a crutch.

[242177P]

Originally Posted by JLMounce

You can always ... cut part of a coil if you need to go down a little bit.

Works on 64-66, but the 67-72 rear springs have a pigtail on both ends. Still, when you consider just how easy these are to swap out...

[gtospieg]

Just an FYI...66 springs CAN be used in a 67 frame...

[rolling money pits]

Thx…

To answer your question, and I’ve seen you ask it in every one of these situations….

#1 Sheer adolescent impulsiveness, lol.
#2A and B ride height and control.

What I was looking at was using something like this

https://www.speedwaymotors.com/Speed...hoCX2MQAvD_BwE

To fit on the axle spring perch, just like the E36 does, for the height adjustable portion. Once that’s been obtained I could source a shock of the proper length which mounts factory style.

The loads imparted on the rear X member are the same as factory. I just don’t get the warm and fuzzies having the spring forces on the upper shock mount area. Plenty of people are using that, so it mustn’t be too terrible.

I haven’t driven an A or F body in 25 years, but my DD is a fairly modern, exceptionally well handling vehicle. I recently purchased a beater GMT400, and going from my DD to that is just a notch or two above horrifying in terms of “road feel”. Haha.

[JLMounce]

Circle track guys use those adjusters frequently. They're actually fairly robust and I wouldn't be worried about that piece of the puzzle.

I actually share some of your trepidation in regards to putting the vehicle loads on the shock mounts. It's one of the reasons I'm almost never for hybrid coil-overs in the front, as the shock mount is now carrying the load. What I would like to see on an A-Body is an upper and lower mount that gets welded in place where the factory coil perches are. It would not be an incredibly tall order (at least with the body off the frame) to fabricate eye mounts in those locations which would solve the shock mount loading issue all together.

The problem there is that I don't think there is enough space to get a proper length coil-over in place. You'd destroy the car's rear travel and have to run such a heavy spring to compensate for it that it would be terrible for a weekend cruiser, let alone anything close to a DD. I completely forgot about the pigtail on the rear springs in an A-body. That almost throughs the hybrid deal out the window anyway.

I will say this; I've spoken at length with Chris Alston's Chassis Works as well as RideTech, about mounting coil-overs via shock mounts. In this conversation I was discussing the fact that both of their front coil-overs use the upper shock mounts. Both claimed they've never seen failures at this point on the GM chassis. Of course you have to take that as a grain of salt, they are trying to sell their products.

What I have seen personally on the front perches is the whole perch assembly cracking and pulling away from the frame. In that situation it was a factory frame first gen F-body that had extensive, competitive auto-x laps using standard coils and R compound tires. Dedicated race car stuff that the factory subframe just couldn't cope with.

That leads me to believe that for a street performance application using typical spring rates, the shock mounts may be up to the job as the product engineers state. I still don't know how much I trust it though and I still don't like RideTech's propensity to use single sheer mounts for their coil-overs.

All that being the case, I'd try a 3" lowering spring along with the adjusters you posted. That gives you the same kind of height adjustability from roughly 2 3/4" up to about stock and you don't have the re-engineer anything.

Road feel on an A-body can get quite good once you get some spring rate in it, a proper shock and make sure the steering is in good condition. My wife's 70 road great with hotchkis springs. In fact, I personally could have gone another 50-100 lbs of rate over those springs given the weight of the car.