Front and rear spring rate and size for stock suspension on Datsun 1600 510?

The stock suspension on the Datsun 1600 (510) typically features front spring rates around 150-180 lbs/in and rear spring rates between 120-140 lbs/in. The front springs generally have a 7-inch free length and a diameter of about 2.5 inches, while the rear springs are often around 8 to 9 inches in length with a similar diameter. Upgrading or altering these rates can enhance handling characteristics, depending on intended use. Always consider the overall balance of the vehicle when modifying spring rates.