From Datsun 1200 Wiki

Lowering the car makes it handle transitions better. And it looks cool. A common way to achieve this is:

• Fit ready-made lowering front coil springs
• Re-arch the rear leaf springs (or fit lowering blocks).

These and more advanced lowering methods are discussed below.

The Nissan Competition springs (PN 54010-H1070) are 110 lb/in rated and lower the 1200 about two inches (see Front Suspension Specification). A 1/2 thick bump rubber stop must be installed on the shock rod. These can be made by cutting down the stock rubber bumpers.

Using stiffer springs can lower the car further, but steps must be taken to keep the spring from falling out of the lower seat at full suspension droop. The end coils of the spring must be securely wired to strapped to both the top and bottom seats.

Cut Springs Yourself, or Pay a Professional to Them?

If you need extra stiff springs, or want to carefully match the springs to an intended result, you can't go wrong by working with a professional, reputable spring company. Since their business is springs, they presumably won't make stupid mistakes like cut the springs too far…

Spring vendors include:

• King Springs
• Eibach
• Koni

On the other hand, If you just want to lower it a bit and are not concerned about racing, I cannot see paying some company to get slightly stiffer, shorter springs, when cutting mine would give me the same thing (with little to no cost). After all, that's what many race car teams do.

Rear Suspension

• Lowering blocks are the low-buck solution, but using modified springs is a better way. The spring eyes can be "reversed" or the leaf(s) can be flattened

  discussion: reverse eye leaf suspension (http://datsun1200.com/modules/newbb/viewtopic.php?topic_id=7752&forum=1)

  discussion: Lowering rear end of a 1200 (http://datsun1200.com/modules/newbb/viewtopic.php?topic_id=6562&forum=1)