Moog 5610 front coils + heavy engine = which shock size?

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454GrandPrix

Master Mechanic
Jul 27, 2016
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Lehi, Utah
Now that my new rear springs (Moog 5391) and shocks (KYB Gas-A-Just KG5508) are in place, I am thinking about quickly installing new front springs and shocks even before swapping in my Chevy 454 + 4L80E. I've already decided to run Moog 5610 coils, so that decision has been made. I like the Gas-A-Justs, as you may have guessed, so I plan to run a pair of those up front.

KYB says our stock-size replacement (for any model with any engine) is p/n KG4513. This shock has a compressed length of 8.58" and an extended length of 13.03". As far as I can tell, the 5610 springs can handle the weight of the big block engine... but will the resulting height still keep me in the acceptable range for these shocks? If I sound paranoid, it's only because I had to install taller rear shocks in the rear to cope with the added height of my stronger rear coil springs. I'm trying to choose the right parts the first time.

Does anybody have any experience to share that can confirm (or disprove) my thought process?
 
no matter how heavy the engine or how tall the springs are the expansion travel is limited in the front by the upper control arm and the compression travel is restricked by the stops on the lower control arms so you have no worries
 
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IMO the 5610 spring is way too soft even with a SBC, with the BBC/4l80E I would almost bet is will be pretty squishy in the front. IDK I guess it all boils down to what you want. I had a set of 5610's in the front of my first G-body with a SBC and after years and years the car looked like it had an invisible snow plow hanging on the front. I am currently running 5662's and love the nice firm ride that my SS has, it's not too harsh and I have no body roll what so ever on any turn. I would think with the BBC that 5658, 5660, or 5662 would work a lot better unless you are wanting to run the 5610's to get the front to "pop up" for straight line racing
 
I am having too much "bounce" in my front end when going over bumps. I actually scuff the wheels on the inner wells on heavy bumps. I minimized this with adjustable QA1's set at max setting, but still have the issue. I have a Regal with a 383sbc that has aluminum heads and intake, I don't remember the Moog #, but they were the ones rated for standard V8 and they are not enough
 
I had a set of 5610's in the front of my first G-body with a SBC and after years and years the car looked like it had an invisible snow plow hanging on the front. I am currently running 5662's and love the nice firm ride that my SS has, it's not too harsh and I have no body roll what so ever on any turn. I would think with the BBC that 5658, 5660, or 5662 would work a lot better

This is interesting. Your 5662s allow for 1,693 lbs of spring force at their 10.75" load height. The 5610s allow for an additional 52 lbs (1,745 total) at their load height of 11.0 inches, which would increase to 1,850 lbs if I allow them to settle down to the same 10.75" load height as your 5662s. On paper, that difference of 157 lbs would certainly make up for some of my added bulk.

Having said that, I admit I like the idea of a bit more spring rate to deal with my lump of cast iron. But because I also don't want my front end to sit any lower than stock, it seems like 5658, 5660 and even 5662 will not work for me. Doing the math, even the 5664s will only support 1,678 pounds at a stock 11" load height (though at 767 lb/in spring rate, they certainly won't droop as far as any of my other choices). Hmm.


Irony: I started this thread to solidify my choice of shocks. I have done that, but now I am questioning my choice of springs. 🙁
 
I'm under the impression that 5660's, uncut won't lower the front of the car, especially compared to tired original springs.
 
If you look at my media content I have a pic of my SS with 5662's unaltered, then another pic of the 5662's with half a coil cut and 2" drop spindles. This is with my aluminum headed SBC 406 in the bay, so the extra weight of your BBC would bring down the height some.
 
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I am having too much "bounce" in my front end when going over bumps.

I have a Regal with a 383sbc that has aluminum heads and intake, I don't remember the Moog #, but they were the ones rated for standard V8 and they are not enough

According to Summit, the Moog 5598 and 5600 front springs were only used on Regals with V6 engines. However, the Moog 5602 and 5604 front springs were both used on Regals with V8 engines. Therefore, I'd wager the 5602 and 5604 would count as standard-duty V8 springs. Because they have a low spring rate of only 346 lb/in, I expect they would feel a bit soft over bumps.
 
I wasn't going for stock ride height but I have Moog 5608 front springs in my Monte with my 565 BBC with aluminum heads,the block is heavier than a 454 but obviously the heads are lighter, glass hood, big Griffen aluminum radiator and a lot of accessories to make it all work on the street which all add weight on the front end. I put 2" lowering springs in the rear to even it out.
 
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