Deflection guages (dealer speciific) are used to measure this angle, I don't see how it can be done without the dealer tool. The best way you can measure ride height is from the center of the star on the wheel to the underside of the fender lip. Early 124's were HIGHER than the later models, reduced by 10-12 mm. Yours is LOWER than the early 124 cars. Most of the later 124's I meaure are about 15-15.25 in front, and 0.25 higher in rear. Mine's made in 8/86 and now measures close to 15-3/4" front and rear after I rebuilt it. Try it with a full tank of fuel for a baseline. Is your problem that your car is riding too high??