Ex850R https://www.dvs.net.au/He can have anything made and knows what's needed for whatever you have in mind for car.
Major Ledfoot JFTR, the factory optional 140 spring specs are as follows: wire thickness = 12.64 mm [0.50 inch]OD = 127.60 mm [5.0 inches]turns = 8.5loading for compression of 1 inch = 112 to 117 lblength at load of 477-510 lb = 283mm [11.0 inches]