Rear coilover shock & spring recommendation

[Phils69 27]

I am ready to order the rear shocks/springs for the four link rear suspension I am installing. I need to know what what lb spring works good on our cars for street driving. Does anyone know the car weight on the front and rear?  If anyone has some suggestions it would be appreciated.

[RPM 1,190]

I've played around with several from 150 to 210 lbs on my QA1 12" springs. I currently have the 210s on it which I'm happy with. I've got 325s on the front, and with a 1-1/8" front sway bar the car is really balanced at speed thru the corners. 

[mustangstofear 608]

We do 250 lb in the rear and 450 in the front. 

[Phils69 27]

Thanks for the feedback guys. I'll pull my receipts and see what springs I have on the front then go from there.

[RPM 1,190]

Phil, based on my research I'm convinced it's like asking what color to paint a car. Ron Morris uses 350# front and 150 rear. A couple guys I know use 300# fronts. I've decided to go the light spring firm shock route. All roads lead to Rome.

[Phils69 27]

Understood. I just want to make sure I am in the ballpark the first shot at it. Do you run a QA1 shock as well? I was thinking of getting theirs as a set?

[RPM 1,190]

Yes I do run the QA1 coil over, #DS501 single adjustable. 

[Phils69 27]

Bob,

You wouldn't have any pics on what your top bracket looks like for the coilover and where its attached do you? I have bought a pc of tubing and am thinking of attching it to both inner frames and building a bracket off it for each side? That looks like what some kits do.

[RPM 1,190]

Not the best pic, but I bought from Ridetech back circa 2005. It attaches the coil overs and upper angled control arms. Mounting spots are circled. 

[Phils69 27]

Thats what I was thinking of doing with the cross bar. Thanks for the help!

[waketek516 10]

On 1/19/2021 at 12:02 AM, RPM said:

Yes I do run the QA1 coil over, #DS501 single adjustable. 

Is that the PN for the rear coilover?

[RPM 1,190]

Both front and rear shock for my home brew application. 

[RogerC 136]

I have the  DS502 for the rear,  same as 501s but poly bushing mounts. 501s are bearing mounts.

[RPM 1,190]

That's interesting Roger. I thought I ordered the bearing mounts, but received the poly. I guess the box was misfilled.

[Phils69 27]

The DS501'S I ordered came with the COM8T-102PK bearing mounts. Did you guys use the optional thrust bearing kit, P/N 7888-109,  for making adjusting the coil spring adjustments easier?

[RPM 1,190]

After buying my QA1s, but before driving my 69 I found the thrust bearings were available and bought a set. 6 months or so ago I bought a set of 501 bearing mounts. I've swapped out the rears, fronts await. 

Edited January 29, 2021 by RPM

[Phils69 27]

I have the suspension bolted in and the ride height where it was before the 4 link swap.  I have the coil spring adjuster near the bottom to get the height correct with the 200lb springs. I guess I will try it here when I get the car back together but if I dropped to 150lb springs I would probaly have the ability to drop the rear height a little If I wanted right?

[Mach1 Driver 560]

After seeing the picture above I had to share this recommendation from Popular Mechanics:

The only appropriate place to jack up a car is on pavement. And in our case pavement means concrete, not softer asphalt. A jack stand can make a nice cookie-cutter hole in thin asphalt. And that's especially true on a hot day, when the sun has made asphalt the consistency of molasses. Speaking of stands--always use `em, folks. Concrete block is not acceptable, because it's far too frangible. There are really only three options: ramps, old-school jack stands and, of course, a hydraulic lift. 

[RPM 1,190]

Good point Terry, I was thinking the same thing. 

[Phils69 27]

The car is being supported on a rotisserie as you can see in the background below. The blocks were being used to represent ride height not to support the car when I’m under it. Jack stands were used as well

 

[RPM 1,190]

Good to know Phil. 

[Phils69 27]

Thanks for the concern and info. Judging from the first pic I can see why you guys were bringing the safety concerns up and rightly so. How about the spring question I had? Any thoughts?

[RPM 1,190]

Do you have a choice of upper and lower shock mounting locations? I do and it makes it easier to raise or lower it by an inch. If you don't, the only adjustment you have is in the threaded shock. If you start out at the lowest location for the locking collar you will only be able to raise the rear height. If you swap to 150# springs the softer spring will allow the rear to sit a bit lower. How much, I don't know. 

[Mach1 Driver 560]

18 hours ago, Phils69 said:

The car is being supported on a rotisserie as you can see in the background below. The blocks were being used to represent ride height not to support the car when I’m under it. Jack stands were used as well

Well now it makes sense- I was wondering what kind of gyrations it took to get it up on those blocks ;)

[Phils69 27]

I just made one location point top and bottom. I mocked up the ride height and had the eyes of the shock at a length of 14" when I tacked the brackets on. Hindsight I would have added a couple more points on the lower for adjustment. I'm going to try it where it sits and let everything settle in then make changes from there.