"Real" coilovers use a threaded body as opposed to a threaded sleeve that slides over the body.
It's the result of a rule that is worded in an interesting way.
It was written before my time, so I can't say, but maybe it was an effort to create an inexpensive way of acheiving the same results, or maybe it was just an unforseen development!
Speaking of unexpected developments, check out the rule that allows "traction" devices on live rear axle cars (yours), start thinking creatively, then go to the G-force engineering web site. Jim Susko advertises his "Tri link" product in the back pages of Sportscar.
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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]