I flexed my genII coils in Betsy II and III, and never had a problem (I first suggested this swap in about 99 or so, and then proceeded to run them hard from 99 till 05 in a shorty and then in a limo GenI. They are still in Betsy III today, and have never moved out of place. They also improved the handling of both trucks, since they are variable rate instead of constant springs.

YMMV


1991 HZJ77, 1999 KZJ90, 1999 UZJ100, 1992 M101CDN2
https://www.thegearheadproject.com/category/jdm-journeys/