1934 Plymouth Coupe - Triangulating Quarter-Elliptics - Tech

After double-checking his measurements, Jason tacks a set of tabs for the axle end of the quarter-elliptic springs to the bottom of the axle, perpendicular to the centerline of the tube. (Finish welding will happen later.)

Getting ready to add the radius rods, Jason sets the caster at 3 degrees (knowing under load with the engine, trans, and other sheetmetal installed this measurement will increase to 7 degrees). At this point Grimes also figures out the length of the radius rod needed.

Jason used '40 Ford wishbones to create the small radius rods. He lopped off the ends and, at the rear section, drilled out the inside to accept another of his custom bungs.

With the bung welded in place inside the shortened radius rod, Jason threads the bung for the Speedway Motors rod end.

Here is a before and after shot of radius rods. The 2-inch bushings on the thick end of the radius rod came from SuicideDoors.com.

With the radius rods in place Jason can figure the location of the remaining four mounting tabs on the top side of the axle. These tabs are mounted in line with the radius rod, so they are not perpendicular to the centerline of the axle.

Jason is using quarter-elliptics with the rear axle suspension too, and he set the adjusting screw inside the `rail before it gets fully boxed.

The kick in the rear of the frame is extreme, but necessary to get the coupe down on the ground where Jason wants it to be. The framerail will be fully boxed after all of the custom modifications are completed.

Grimes severely modified the Plymouth's stock X-member to get it to fit his custom framerails, but now the chassis is well on its way to getting thrown under the coupe body for good.