Springs.....................

[NavyCPO]

When I look at my car, it looks to me like the front end sits pretty low and pretty low over the tires like the springs are seriously worn.  Today I noticed that it looks like the passenger front is a bit lower than the drivers side and the back seems like the drivers side is a little lower than the passenger side.  I put new airi shocks on the back and they raised up the rear a bit and I haven't checked to see if it helped level the back up yet, I think it did some.  But being a SBC Car is it common for these cars to sit so low in the front end?  And is it common to have to replace the springs on these old girls?  Mine is a 70 so she's 53 years old now.  Or could it just be me?  Also if I take measurements and she is sitting lower on the passenger side, what are ya'll's (that's a southern word) thoughts on using some of those spring spacers to level her up/give her some support until I could get some new replacement springs?  Should I order BBC springs or stick with the SBC springs and just freshen them up.  GO!!!

[420ponies]

As for the front springs, I had bought these through Lutty's. Just look for your fit ,A/C or non ,SBC or BBC. As for the rear I use the Moog Vari - Rate just because you can load the trunk and no sag. Also, I have Air shocks and run 25 psi just so they work running down the road.

[MC1of80]

The pic you have shows your car sitting just fine. Although it is not uncommon to have a weak spring. I would first look at the shocks and if questionable, replace with a gas type shock of your choice and then measure the ride height. 

[Dtret]

As said above correct spring for the application. You probably don’t want big block springs, may sit to high for your liking. Yes check shocks as said. You can get by with spring spreaders for a little while. The twist in ones can pop out on big bumps and the bolt on are a pita. 

[cny first gen 71]

It doesn't look like it's sitting to bad. Take some measurements to know  for sure. On mine the front springs have been changed at some point before I bought the car. I changed the rear with cargo coils and added spacers to the bottom to get the stance I wanted. At different angles it will look different. Put it on a level surface and measure all 4 points and see. As far as the front spacers I've personally never liked them.

[MCfan]

Dale, do you have a Build Sheet for your '70?  If so, check box 13 for the 2-letter code identifying the spring that GM selected from 10 possible front coils when your Monte was assembled.  Even if your front coils have been replaced or sagged over the years, the specs for the spring used in assembly (see spring table below) should get you back to "stock" front end height for the options originally built with your car.  You are not going to find the original part numbers for replacement springs so you have to compare the original specs with specs of available replacement springs.

As you look down the table of 10 possible springs below, you will see that the springs increase in preload force (pounds at working height of 11.7" in the far right column) from 1360 lbs for the "lightest" AF spring to 1760 lbs for the "heaviest" GQ spring.  Your car was built with the spring that had the best preload for its total weight, including options. While small blocks obviously weigh less than the big blocks, engine choice was not the criteria for factory spring selection which was based on total weight including all options. For example, my low-optioned 402 4-speed '70 was built with the AO spring while a heavily optioned small block automatic car may have been built with a heavier spring.

Because I added AC, power steering and larger front tires, I chose to install 1" spring spacers in my original AO front coils to avoid tire rubbing on tight turns.  I used the split-circle 1" rubber spacers near the bottom of the coil (see photo below) to get some minor lift without stressing the spring.  I would personally never use those metal plugs that twist-in between the coils because they create stress points during operation.  As you may know, spacers effectively reduce the working height of a coil spring and thereby increase its preload so use them in moderation.

Coil springs can take a "set" and/or weaken over the years, so if you decide to replace them (instead of using spacers) you will need to calculate the preload of the spring you select to either match or slightly exceed the preload of the original factory spring.  The calculation is easy once you have the following spring specs: free height (in inches) and deflection rate (lbs/inch of compression).  Simply subtract 11.7" (working height) from the spring's free height and multiple that difference by the deflection rate. For example: using the popular replacement Moog 6330 specs: (17.5" - 11.7") x 293 lbs/in = 1700 lbs of preload. Now compare that to the preloads shown in the right hand column of the table below and see where it stacks up (almost the same as the AQ spring in this example).  I agree with others that you probably shouldn't select a spring with the heaviest preload unless you want the front end to sit pretty high.  Preload is definitely the most critical factor in determining the static height of your Monte's front end. Good luck.

[Whons]

Interesting. Where did you get those rubber spacers in the pictures of your springs? I just redid my front end suspension and took exactly 1" off the bottom of the springs. It lowered the front end 3" which I wanted, but the height  of the front end varies a little side to side. I'm going to drive it awhile to let the springs level out. but if I need to I would like to know where to get those rubber spacers. Thanks Wayne (Whons)

[MCfan]

Wayne,

It's now been over ten years since I rebuilt the front suspension on my '70 4-speed car so I don't remember exactly where I acquired those rubber spacers, possibly eBay. They were Dynachrome brand but others probably make them, also.

I see you can currently buy them by the pair on Amazon for $42.99 at https://www.amazon.com/Rubber-Coil-Spring-Spacers-Pair/dp/B075NRCL8W  Other places may carry them also at better prices so you may want to shop around.

I really do like them for several reasons.  They are easy to install and completely silent.  Also, they do not create stress points in the coils like the twist-in metal spacers that are commonly used. Looks like I installed mine during the frontend rebuild because I had just installed 255/60-15 tires on 15x7 rims with 4.5" backspace. BTW, those are the stock AO springs, I just like to clean and paint any parts I reuse in my projects.

I don't know if you will need disassemble anything to install them (they hopefully come with instructions). As a minimum, you will need to jack up the front end, remove the wheel and pretend you are Houdini while you thread those spacers between the coils. Worst case, you may have to disconnect the upper ball joint and drop the lower A arm down with a floor jack to get enough space between the coils.

While I installed mine at the bottom of the coil, I don't think it matters where in the coil stack they are located.  Anywhere in the stack should limit the total spring compression the same.  Good luck!

[Whons]

Dennis, thank you very much. 

[S.Maug]

Going to rebuild sin city's front end as soon as I lick this cancer.  Nice job Dennis

[Jeff Dodson]

On 6/15/2023 at 1:54 PM, cny first gen 71 said:

It doesn't look like it's sitting to bad. Take some measurements to know  for sure. On mine the front springs have been changed at some point before I bought the car. I changed the rear with cargo coils and added spacers to the bottom to get the stance I wanted. At different angles it will look different. Put it on a level surface and measure all 4 points and see. As far as the front spacers I've personally never liked them.

How did the CARGO COILS work for you. I hate, HATE air shocks and am going to go with Cargo coils

[cny first gen 71]

4 hours ago, Jeff Dodson said:

How did the CARGO COILS work for you. I hate, HATE air shocks and am going to go with Cargo coils

They work great, I do put extra weight for camping equipment occasionally but did need a little more lift so installed the spacers.

[S.Maug]

I installed rear Moog variable cargo coil springs and Monroe front and rear spring assisted shocks on Sin City in 1980 because 1 rear shock was missing, and the other was leaking. stance, ride and function has been excellent. I am going to rejuvenate the rear auto level when Dennis rounds up a few pieces I'm missing. Going to rebuild front suspension soon also.  just shouting out to anyone interested.

[Dtret]

31 minutes ago, S.Maug said:

I installed rear Moog variable cargo coil springs and Monroe front and rear spring assisted shocks on Sin City in 1980 because 1 rear shock was missing, and the other was leaking. stance, ride and function has been excellent. I am going to rejuvenate the rear auto level when Dennis rounds up a few pieces I'm missing. Going to rebuild front suspension soon also.  just shouting out to anyone interested.

I’m still on it. No worries. 

[Grant MacPherson]

I used Moog cargo coils and they are great, far as the air shocks I love them. Since I traced down all the minute leaks and the compressor is working as intended the car can sit for 4- 5 weeks and still have over 90 psi in the tank.

[Jeff Dodson]

I'm waiting for the shocks to come in the mail... should be here tomorrow... now we are looking at BERYL hitting south of us... I'll see if I can get them on tomorrow even or Sunday morning... either way, my Monte will be secured in my garage

 

 

 

Well, got the Monroe coil assist shocks yesterday and put them on. Gave me the stability I was looking for. 

[S.Maug]

Stay safe jeff. 

[NavyCPO]

On 6/15/2023 at 1:09 PM, MC1of80 said:

The pic you have shows your car sitting just fine. Although it is not uncommon to have a weak spring. I would first look at the shocks and if questionable, replace with a gas type shock of your choice and then measure the ride height. 

I put air shocks on it. Still looks crooked to me.  Perhaps springs are in the budget this year.  I like the raised stance in the back for my taste.

[72 Monte Carlo]

I bought a brand-new set of Moog CC507 variable rate rear coil springs, and a new set of rear upper and lower UMI Performance control arms for my 72. I'm going to install them after my car is painted. I'll install them along with the new Yukon posi and 3.31 GM gears in the 12 bolt. 

[NavyCPO]

On 5/15/2025 at 3:24 PM, 72 Monte Carlo said:

I bought a brand-new set of Moog CC507 variable rate rear coil springs, and a new set of rear upper and lower UMI Performance control arms for my 72. I'm going to install them after my car is painted. I'll install them along with the new Yukon posi and 3.31 GM gears in the 12 bolt. 

CC507 says they are for Pontiac Grand Prix.  Will they also fit 1st Gen Montes as well?

[cny first gen 71]

15 minutes ago, NavyCPO said:

CC507 says they are for Pontiac Grand Prix.  Will they also fit 1st Gen Montes as well?

Yes they will

[NavyCPO]

Thanks Steve!