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Discussion in 'LS-427' started by fasteddie, Jul 12, 2015.

  1. fasteddie

    fasteddie Member

    Need new shocks, hear QA1 are good. Anyone have part numbers?
  2. Barnsnake

    Barnsnake Member

    It depends upon what tires you are using. Cars with 15" or 16" wheels generally run 10" springs. Many with 17" wheels (and smaller O.D. tires) run shorter springs and shocks to avoid the 4x4 look.
    If you can supply the diameter of your front and rear tires, someone with similar equipment can give you an accurate answer.

    BTW.... The QA-1 shocks are EXCELLENT!

  3. 427GTO

    427GTO New Member

    I have the new 427gt, I have 15" wheels and have the 7"QA1 shocks with 7" springs. With the 9" shocks it definitely had the 4 x 4 look, even had to change he front spindles to 2" dropped spindles.
  4. fasteddie

    fasteddie Member

    I am running 17" tires all around. What shock part number and what is the cost?
  5. Barnsnake

    Barnsnake Member

    Come on guys! I know several 17" wheel users out there have gone to QA-1's and 7 or 9" springs. Help Ed out here.

    Ed: Most everyone I'm familiar with has used the single adjustable shocks with the spherical, non-compliant bearing mounts. If you're getting shocks and springs I expect it will run you about $200 per corner. Shocks only about $170 from Summit, etc.

    If you're happy with the current stance of your car, find a way to measure the current installed length, bolt center to bolt center, of your shocks with the weight on the wheels. While you're there, see how much more compression travel you have before you hit the rear bump stops. (This is a good time to check whether your bump stops are truly effective, or you actually run out of shock travel (BAD!!).)
    Check the QA-1 web site and determine which Proma-Star coil-over will give you that length at roughly 60-65% of its maximum extension. (I personally think you need more compression travel than rebound.)

  6. Cowtown

    Cowtown New Member

    Don't remember the dimensions but Summit has a nice return policy.
  7. cobrapilot

    cobrapilot Member

    The QA1 part number is: QA1 Proma Star Coil-Over Shocks DR3955B
    The front springs are 7-350's and mine are adjusted about halfway up the threads with 17" wheels.
    Ideally, you want the lower control arms to be horizontal when the car is at rest. This gives you the maximum travel in each direction.
    If you don't have one, you should also get a front sway bar. Let me know if you need it and I'll dig up the part numbers for that too.

  8. fasteddie

    fasteddie Member

    I do not have a front sway bar, what is the part numbers?

  9. cobrapilot

    cobrapilot Member


    These parts are from http://www.1speedway.com
    Speedway Engineering...

    These are the parts I used originally:
    Sway bar: 608-188-32 (0.188" thick wall. 1.25" dia.)
    Arms: 617-3 (30deg. offset steel arms. 48 spline)
    Pillow Blocks: 605B-125S (Low profile 1.25" dia.)
    Shaft Collars: 605C-125 (1.25" dia.)

    Now that I have my rear suspension completely rebuilt as an IRS, I'm planning to go with the heavier bar:

    The pillow blocks above will mount to the front of the forward cross brace / radiator lower mount. Slide the bar into them and drill holes for the pillow blocks. There's not a lot of room, but I used a right angle drill and one of the harbor freight step drills. Those things work great on thick material.

    Different people have done many different things with the arms. I preferred to have the arms above the lower control arms, so as not to have parts hanging down low. I welded braces to the lower control arms which connect to a heim link, which in turn connects to the sway bar arm. With this, I was able to use the arms as is with no modification.

    The shaft collars go onto the sway bar and against the pillow blocks to prevent the sway bar from moving laterally. The 32" bar will place the arms just inside each coilover, about 1/3 of the way up. Some people have gone outboard of the coilovers by bending the arms. It's all up to you.

    You will want to powder coat the steel arms, or use the aluminum ones. I recommend removing the coilovers temporarily, and making sure the sway bar setup does not interfere with anything in the suspension's range of motion.




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