Anyone tried the 5658 or 5660 springs in the front? Would the ~600 lb rate be too much? I'm about to start a front rebuild and am looking for options that dont cost as much as the "performance" brand springs. I'm rebuilding with rubber up front to save money as well as for the isolation it provides. What would be a moog # for a good match for rear springs? I'm thinking around 200lbs. THe 5413's I believe are around 170. Front sway is 1.25 with the stock 7/8 rear bar. I assume stiffer rear springs would reduce the understeer a bit without having to increase the rear sway diameter. Any suggestions to help my ignorance on the subject would be appreciated.

Or would I be better off sticking with the 5536 and 5413. The car is driven hard at times but not raced. I dont mind a real firm ride just not harsh.

By the by...I bought Rear LCA's ~20+ years ago that were TRW's with high durometer bushings from a buddy at my local auto parts. Full box, heavy gauge metal, painted red...completely got rid of the rear tail wag. Never seen or heard of these anywhere else. Anyone seen these before? I could post a photo if anyone wants.

Does it understeer now? If you're experiencing understeer, you're probably driving it harder than most here do, so you may want to really step up the spring rates.

With those sway bars and a Big Block, 600# fronts and 150# rears should work pretty well, and if you're still experiencing understeer, try a 1.125" front bar on it to reduce the front roll-stiffness a bit.

What else has been done to the suspension? Any geometry mods, or change in bushing materials? If running stock front spindles, you may have a hard time getting it to not understeer, and if running poly bushings in the rear, its non-linear roll-stiffnes may cause snap-oversteer if you can get the front to bite.

Derek,

It pushes some in hard cornering. No poly or geom changes, I wanted to stay with rubber for the isolation and I've always felt new rubber(the higher duro problem solver) works well. No poly in the rear, just the TRW lowers as described. Rather than soften the roll rate up front I was looking to stiffen it in the rear (lol) with springs to match the higher rate I'm contemplating in the front. Having never had 600# springs in the front I'm not sure how harsh it gets. THe 5536's are 488# I believe. I guess I'm just loooking for a nice balance. When money gets better I plan on the S&C stage 2 mod. Perhaps Marcus will chime in with his knowledge.

600s will ride just fine, in fact, I love my 700s with my smallblock and solid bushings, and I may up it to 900-1000 next time I have it apart.

The 600# fronts will increase the roll-stiffness some, which is why I mentioned going to a 1-1/8" front bar if it still pushes.

Fixing the geometry is very important before you spend too much time and money getting it balanced with the current poor geometry. The SC&C Stage II package will make the front bite much better in the corners, which will make it easier to tune properly with springs, shocks, and sway-bars later.

"The SC&C Stage II package will make the front bite much better "

I hope to get this but got layed off and money is tight so I'm doing this on the cheap. I pulled the front end apart and what do you know 5536's are already there. I guess thats what happens when you have a car 30+ years...forgot I put them in...duh.

Any idea if the 5660's will ride about the same height? Looking at the spring chart I posted it seems they might ride a bit lower which is not really my goal. Perhaps the 5662's if that is the case. I can swing the 60 bucks either cost.

Both upper and lower ball joints still take some force to move. The uppers are original and the lowers were replaced probably 20 years ago but dont have more than 20,000 miles on them so for the time being they will stay. I'm putting on the poly boots and I cleaned them out real good...no scoreing. I'm suprised that the 30 year old uppers are still fairly stiff to move.

Anyway thanks for the input.

sc&c recomends 5413 for the rear and 5660 for the front in a more serious car. They should lower the car one inch from stock. I have a set of the 5413 coming this week.

I thought I'd update this. I talked to Marcus(nice guy btw) and the FAQ is a little unclear. The recommandation for the 56xx springs is for G bodys not A. I got a set of the springs but they will not fully sit in the lca pocket. They would probably work with an aftermarket lca. I cut a half a coil off the 5536's, replaced all tie rods, bushings and upper crosshaft with problem solver stuff and did a ballpark align with a level and tape measure. The results are amazing. I had neglected to front end and the alignment(done years ago) was probably using the factory specs. Even in its ballpark state the car is stable, tracks straight, no squealing in corners, smooth and quiet. The half coil cut from the 5536's worked out real well and seemed to only drop the front a half inch at the most.

I ended up putting 5/16's of shim on the front and 9/16's on the rear. The level layed across the disc face and the tire when mounted showed a very slight neg camber. To show 0 the level had to move away from the top about 1/8th of an inch at most. A tape measure pulled across the tire front and rear shows about 1/16 to 1/18 toe.

Anybody have a ballpark idea what the caster would be with the shims installed?

This will do till I get the time to get it done right as I dont drive it daily.

I'm rebuilding the front suspension on my 72 Chevelle (307) using a polygraphite kit. Probably Monroe Sensa Tracs. The guy I bought the car from gave me a set of new springs. Part# U5536MK (Moog 5536?). Are these strictly for BB's? Trying to get by as chea...inexpensively as possible. Two kids in college. I believe the suspension is basically original, so even a chea...inexpensive rebuild will at least make the car safe. Any advice will be greatly appreciated.

The 5536's say BB but would work. I would rebuild and put them in. If you need lower start with half a coil off and go from there.