Mike - Dave S' info on Speedway is right on. Summit, while I buy lots from them, IMHO, caters more to the later models and 1/4 mile straight line crowd.

There are a several on-line formulas, but way beyond what you need for a hobby car.

The AFCO charts are right on, either their web site or Speedway. As far as length, coil free height and wire diameter, total diameter, etc., those for your car are pretty cut and dried. You most likely have a 10" x2.625id and somewhere in the 200 in lb rears at 10/15 degree inclination, which puts them at about 180 in lb effective. The fronts - same size, but probably 325 in lb, with a final rating at that 10-15 degrees of ~300.




This was a project I did last winter, both front and rear