What's the consensus on replacement spring shackles? I'm running a set of nice NOS units on my 1936 sedan, the only problem is, they creak and groan like an old man climbing a flight of stairs. I've tried tightening and loosening the crossbars and attempted to get some penetrating lubricant into the rubber, but nothing has made any difference whatsoever.
I hear there are some newer replacement-type shackles that might be better, but I'm not sure what would work best. I hear urethane bushings squeak just as bad or worse. These nylon ones from Speedway seem highly rated, but I'm not sure what's best.
https://www.speedwaymotors.com/Trans...ings,2083.html