I posted Ecklers full kit for your 1972 C3 in a post last week
They have been selling Corvette parts for over 30 years and would think the amount of Corvette owners buying from them
if this kit has bushings issues, they would not be selling them to this day
Ecklers Hyper-Flex System Complete Bushing Kit; Black (63-82 Corvette C2 & C3)
Performance-Enhancing Bushing Kit. The Hyper-Flex System Complete Bushing Kit is designed to dramatically improve the handling and control of your Corvette. Thiwww.ecklers.com
This gives you all that is needed and would allow replacing them all at one time or save ones not replaced
to change in the future as you see this has all the bushings, mounts, sleeves, washers, bolts, etc
View attachment 27899
Yes a kit. I have that kit in a my Summit Jegs and Ecklers as from when you mentioned them. I went off Poly a bit due to folk saying there no good but then as you say. Energy are still going strong after all these years and top suppliers are selling them so must be still good.