In 2001 when I pulled the 318 and swapped in a 440, the car weight went up by 90 lbs.
The 318 had A/C and was all iron. The 440 had an aluminum intake, aluminum radiator and no A/C. I thought the weight difference would have been greater. I went from stock torsion bars to the Mopar Performance 1.0" set. Yes, the car rode stiffer. Common sense tells anyone with it that a stiffer spring would deliver a stiffer ride. I didn't know how crucial the choice of shock absorber would be, I went with what was cheap and widely available. For many years, I drove lowered vehicles that rode stiff so maybe the standard of what is acceptable is different for me.
Never have I experienced a "teeth rattling" ride in any car, even the lowered ones. That description that some people use has never been what I would use.
Torsion bars have not evolved much over the years but shock absorbers have.
You can have a shock that, for the lack of a better term, tames the frequencies of the spring rate.
When I changed to the 1.15" bars, I changed to Bilstein shocks at the same time. I expected a firmer ride but much to my surprise, it was similar but smoother. There was less lean, less brake dive but fewer shakes and rattles. I won't state that the 1.0" bars and KYB shocks delivered a "teeth rattling" ride but it was not smooth. The bigger bars were a better match for the car because of the shocks. If I had kept the 1.0 bars but changed the shocks, I may have felt that the front needed more spring rate. Good handling has been my primary goal since I first started driving.
My limits of ride tolerance may be higher than the guys that grew up where it was popular to raise cars up. In the 80s, we lowered our cars and trucks. A firm ride was what we were used to feeling.
