Dear Welder Series… leaf springs vs. four link

Dear Welder Series…
I’m building a 1940 ford pickup.  I’m having a hard time deciding on the rear suspension.  I’m between a basic parallel leaf spring set up and a triangular 4 link.  When it’s done the truck will be a driver.  I’m not intending to haul 2 tons of rocks but I would like to be able to go to the lumber yard on occasion to pick up a few sheets of plywood or a few 2×4’s.  Front suspension will be one of your MII coil over kits.  Rear end will be a ford 8.8 with traction loc.  Can you offer any recommendations to help me with my decision?

Thanks.

Jack

Dear Jack…
Jack, here are some advantages of both systems:

Rear leaf springs

  • Bolt-in installation.  (You will have to weld spring pads onto your axle.)
  • Price.

Coil-overs/triangulated rear 4-link

  • Easy to change spring rates to fine tune the ride.
  • The cost of new springs.
  • Heavier-duty, higher quality shock than the standard ones that come in a standard leaf spring kit.
  • Easy to change pinion angle.
  • The coil-over has a designed ride height. Upper and lower mounts can be designed so the truck’s ride height will be where you want it with no guessing.
  • Ride height is adjustable by using the lower coil-over mounting bracket holes.
  • Ride height can be dialed in when different spring rate is used. (The lower spring seat can be adjusted up or down.)

I hope this helps with your decision.

Paul Horton

2 comments

  1. Brian says:

    Help w/Mopar A-body (70 dart) spindle,etc.,questions
    If i use pinto spindles will the large (mopar)ball joint fit in the holes. I mean is the taper the same. I bought a rack and pinion and want to get rid of my steering box.i was going to use granada rotors. Any help w the info you have would be so appreciated. I love this site

    • DW says:

      Good questions, Brian. I can only answer some of them.

      There are 2 different Pinto spindles: 1971 – 73 and 1974 – 80. (1974 – 80 pinto and 1974-78 Mustang II are identical.) See http://104.154.121.234/?s=pinto+spindle to compare. I like the 74 – 78 spindles because they are bigger and are the ones commonly used in Mustang II crossmember kits, including ours. 1971 – 73 are often used on drag race cars, probably because they are lighter. There are big brake kits available for the early spindles, but I’d say you have more big brake choices for the later spindles.

      Moog K772 ball joints fit the late spindles, but I don’t know about the early ones. When using the K772 as a lower ball joint on the later spindles, use our K772S spacer and the stock ball joint washer under the nut. Without the spacer and washer, the nut will not draw the tapered ball joint stud into the hole tightly.

      I don’t know if adapter kits are available to put the 73 A-body brakes on the Mustang II spindle.

      Thanks for checking out Welder Series parts. I hope we can help with your project.

      Paul Horton

Leave a Reply