1. CM360

    CM360 Well-Known Member

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    A few weeks ago, I picked up a '81 Diplomat /6 2 door. Topped out at 85 mph and the front end had picked up by the time I hit 65 mph. Definitely driving on a cloud. My other F's are drag car, so I have no idea what it is to drive one of these unless in drag mode They definitely feel better on the top end.. I have a crate motor that makes about 425 HP that will be replacing the /.This car will become a daily driver with power windows,A/C and PS. How do I get this car to handle well? I mean, well enough that I can be traveling btwn 85-120 mph and take a curve in the highway. Right now the front end is tight, alignment good and the tires are radial Dunlops. The 7 1/4 will be replaced by a 8 3/4. My 2000 Ranger feels better on the road than this Diplomat.
     
  2. Duke5A

    Duke5A Well-Known Member

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    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. You should be able to find a matching set for $250.
    • Frame ties. If you drag these cars you know how flimsy the unibody is. 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 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.
    • Good shocks. If you don't go nuts with higher spring rates then a set of the premium Monroe shocks are a good choice.
    • Turn down the pressure on the steering pump. 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. Even BFG Radial T/A will perform well for street driving. 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. These things aren't cheap though at $650. 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!
    • Bilstein shocks on all four corners. These have gone up dramatically in price though since I purchased them. With the cost you might as well look at a set of custom Vikings as those are adjustable.
    • 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.
    • 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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  3. CM360

    CM360 Well-Known Member

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    Great info. How do those B body leaf work since the B and M have different spring lengths? I assume that you are not using a 7.25 or 8.25? That's probably a custom length bar and mounting brackets for the sway bar?
     
  4. Duke5A

    Duke5A Well-Known Member

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    Use factory F/J/M springs and replace the centering pin in the leaf. Use B body shock plates. I can dig up photos of my setup. I ran this with a B body with 8.75" for years before swapping out for a D60 last winter. This is a fairly popular swap that a number of members beside myself have done.
     
  5. kmccabe56

    kmccabe56 Well-Known Member

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    Anybody ever put front and rear sway bars on a wagon? I've been told that adding a rear bar with all of that extra mass behind the rear wheels can lead to snap oversteer.
     
  6. Duke5A

    Duke5A Well-Known Member

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    @Opticon77 is the guy you want to talk to. He's got a real nice wagon he's in the middle of turning into a corner carver.
     
  7. Opticon77

    Opticon77 Well-Known Member

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    1) Wheelbase is plenty long to fight snap anything. Weight transfer in this car is easy especially if you're working to take the lateral wiggling out of it all.
    2) The % of weight that the rear glass represents in the car vs the steel in a sedan is actually pretty negligible. These are more like hatchbacks than the fat old "station wagons".
    3) The car as setup from factory is very prone to understeer. I could probably MAKE a wagon to snap oversteer with all of the wrong parts and settings... but you're not going to do it by accident with a fat front and rear bar kit.


    And Duke, I'm still waiting on my 300# bars. Firm Feel must be having a hell of a time coordinating the latest batch. Someone else get a set on order and help me motivate them.
     
  8. Duke5A

    Duke5A Well-Known Member

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    Heh, already have two sets. I'd have to buy another car and sign divorce papers first.
     
  9. kmccabe56

    kmccabe56 Well-Known Member

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    So, tie the frames, add the bars and voila? I've got NYB 15" road wheels on the car now along with KYBs at all four corners. Years ago I played with a '73 Scamp. DC front/rear bars in poly bushings, six leaf rear springs made from /6 and V8 sets, KYBs in front and air shocks in the back. B-body wagon wheels and Kevlar radials. That car ran like it was on rails.