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70 Mach 1 Competition Suspension Questions (Long)

803 Views 4 Replies 2 Participants Last post by  70calypsomach
Need some help identifying parts that may be missing from my 351C rear suspension. My invoice sheet lists my car a having the Competition Suspension option. My car seems to be missing a few key rear parts. (#'s are from the assembly manual)
I have the following:
1/2 " rear sway bar
Spring bolt plate, non stagger ( P/N 5799)
Sway bar to spring attachment plate plate (P/N 5A775)

The following parts I think I am missing:
3 spacers above rear spring P/N 4137, 5736, 5723
1 spacer below rear spring P/N 5732

I purchased new rear springs from NPD (Eaton) for a 70 Mach 1 351 with competition suspension. What made me investigate was that my ride height seemed way too high. 9.5 '' from axle tube to jounce bumper stop. I should be only 3.66'. I do not have any load on the car. Missing powertrain, interior, rear glass, Etc.. 200 lbs in the rear seat area (me) only drops it 1/4 to 1/ 2".

Did I get incorrect spring or am I missing these spacers to set my ride height correctly.
Any recommendations on where to pick up these parts (Used or Repo)


Mark Memmer
70 Calypso Coral Mach 1 351C 4V Completed by 8/01
98 Cobra Convertible
93 5.0 Mustang LX (Winter Ride)
00 Volvo S80 (Wifes Ride)
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I put a competition suspension on my 70 - 302. It came with a 8 inch and now I have a 9-inch. I have a rear sway bar which mounts to a sway bar plate which sets under the shock plate. The sway bar connects to that with end links. I have staggered shocks. I have NO spacers above or below the shock/sway bar plates. I modeled this after the staggered shock rear in a boss 302. The ride height is just fine. I have new leaf springs (4 leafs) purchased from Detroit Eaton spring, which I had re-arched 1/4 inch. Like you, I have my car gutted inside, so there is no rear weight. I could measure the distance in clearance to the rubber bumper on the rear frame rail, if you wish. I am unaware of any spacers being used in the stock set-up. I think your springs are just to high. You can take them to any good spring shop and get them re-arched for not much money, if that is really your problem. good luck.

sure it's fun, but it's only a car.
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