J BODY LEAF SPRINGS

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CM360

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So, I got the correct info on swapping out 7 1/4 to 8 3/4 rear( on the hunt mode). Now, I'm looking for info on the length of the leaf springs, eye to eye and overall length. Found replacement springs on FFI and by the time I done, CalTracs are cheaper(estimated).CalTracs has in stock FM set ups in stock. I do not have the car in hand(1981 Cordoba). Looking for all the suspension parts that, in my mind, can be a deal breaker if I can't get them. Probably my last FMJ build(318 turbo) street DD. Your help is greatly appreciated. Thanks
 
It's probably going to be a easier using a late model axle rather than hunting for something that ceased production 50 years ago.

Does Cal Trac have normal leaf springs or just the split mono leaf? Mono is going to make for a car that rides horribly on the street.

What's your budget and what's the intent? You can make these cars handle on rails (I have), but it's not cheap.
 
My 1st feeble attempt at turbocharging a 273 netted about 400HP. Plumbing nightmare and before blow thru carbs were around. Just looking at Firm Feel, there always seems to be another add-on and you are still not finished. ESPO is no longer making spring for most cars. They are whittling down their inventory to die out. Maybe that the J platform is just a waste of time, money and utility. Thanks for your info.
 
Used General Spring myself.

IMG_4405.jpeg
 
CM360 said:
My 1st feeble attempt at turbocharging a 273 netted about 400HP. Plumbing nightmare and before blow thru carbs were around. Just looking at Firm Feel, there always seems to be another add-on and you are still not finished. ESPO is no longer making spring for most cars. They are whittling down their inventory to die out. Maybe that the J platform is just a waste of time, money and utility. Thanks for your info.
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I wouldn't call that feeble by any stretch. You doubled the HP of that motor.

Don't get caught up in chasing the entire product catalog at FF. I can give you an itemized list sorted by biggest bang-for-buck for suspension mods. I had a lengthy post somewhere I on this forum. I'll see if I can find it.
 
Espo Springs n Things is still selling FMJ springs, they have a lot left and they're not going out of business anytime soon
 
Funny, I got an email/ advertisement from them stating that they are selling off inventory. I'll have to call. Thanks
 
CM360 said:
Funny, I got an email/ advertisement from them stating that they are selling off inventory. I'll have to call. Thanks
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They're older and trying to get rid of the springs because they're too heavy for them at their age.

I'm almost tempted to buy a 2nd set of springs and hoard them
 
I wouldn't bother, any new ones now should last the rest of the life of the car. The plus with leaf springs is they last for decades and any truck shop can service them if needed. Re arch them, add a leaf, make a new main. They could make a whole new bundle but it's cheaper to get that from places that already do that and there are a few around. You rarely actually have to replace the entire set to begin with but at least we're not screwed if everyone stops selling our specific ones.
 
Mikes5thAve said:
I wouldn't bother, any new ones now should last the rest of the life of the car. The plus with leaf springs is they last for decades and any truck shop can service them if needed. Re arch them, add a leaf, make a new main. They could make a whole new bundle but it's cheaper to get that from places that already do that and there are a few around. You rarely actually have to replace the entire set to begin with but at least we're not screwed if everyone stops selling our specific ones.
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Don't bring logic into this! Hoarding is hoarding lol
 
Following this, I decided to contact Espo Springs. They need three and a half months, for orders. Price is $370.00, for my 82 Cordoba. But shipping and who knows what tariffs may now exist, make them very expensive, to Canada. Although it looks like they are not too far from Carlyle PA!
 
Found that post. Made some updates as it was from 2020:

I've spent a lot of time over the years trying different combinations of parts to get these cars to handle. I'll start the with the best bang for buck upgrades.

  • Cop sway bars. Easily the best and cheapest upgrade you can perform. Get the front 1 1/8" and rear 3/4". The difference even in just changing lanes is dramatic. No more diving into the corners. These were available on fleet model cars with the A38 (prior to 1984) and AHB (1984 and later) fender tag codes. You should be able to find a matching set for $250. You'll need the shock plates off the rear as the non-fleet models don't have the provisions for the end links.
  • Frame ties. The unibody structure on these cars after 40 years is extremely flimsy. All the work you put into the suspension will never be fully realized if what holds it all together has the rigidity of a wet noodle. I paid a local racer to fabricate and install a pair for me as I can't do overhead welding. All he used was 3x1" box tube and tied the front and rear rails together. Nothing special and no bends. Didn't even go through the floor. The difference in regular street driving was day and night.
  • Turn down the pressure on the steering pump with shims in the flow regulator. Greatly increases road feel at the wheel, but does nothing for the slop at center though. This is a real cheap upgrade and can be done for $10. If you don't want to spend the money on the Borgeson washer pack you can make your own from a set of copper crush washers and turn them down using a drill motor, vice and file.
  • Run 235 or 245 tires on all four corners. Stay with 15" unless you want to sacrifice ride comfort.
  • Run a five leaf rear spring and run B body shock plates. Pretty noticeable difference and you gain a very wide variety of shocks as you'll use standard B body pieces.
  • Use poly bushings on the sway bars, but stay away from them on the control arms and springs unless you don't mind the squeaking.
  • Lower the stance of your car and keep the front and rear at the same height. This will present a problem though if you run full length headers. The driver's side will kiss the street due to the soft T bars.

The above all done together will make for a very nice driver without sending creature comfort out the window.

The icing on the cake, but more expensive.

  • Firm Feel 300# torsion bars. The weakest link in the cars was always the junk T bars. Chrysler only made one rate bar for these cars at 140#. 140# sucks. Not even the cop cars got a different bar. I love the two sets I picked up though and would do it again in a heartbeat. Road comfort didn't really take that much of a hit as I was still running 15" tires. You will need better shocks though! I'm not sure if Firm Feel still carries these or not. You would have to call and ask. When I bought my set almost 20 years ago I paid $600. They would be well over a $1k now, but if I was building another M body I would still do it.
  • Viking aluminum bodied double adjustable shocks. These were such a significant upgrade. Regained so much ride quality out of these over Bilstein shocks it was unreal.
  • Borgeson steering box. Want bolt in rack-and-pinion steering? Doesn't get better than this. Faster ratio, smaller box, tight steering, no slop. Once again though, not cheap. I've got about $900 into mine between the box, lines, pump and adapters. Get it all through Bergman Autocraft and use their column adapter for a complete bolt-in kit.
  • Firm Feel tubular upper control arms. Nice upgrades that made a good difference in steering feel. They will squeak a lot with the poly bushings though.
Hope this helps.
 
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