Chevy used '261 valve springs' also in truck 235s with solid lifter cams starting in 1956 and PG car 235s with hydraulic cams starting in 1954.
848 heads always were supposed to use '261 valve springs'.
Correspondingly 261 cams were used in truck 235s with solid lifters starting in 1956.
And the hydraulic version of the 261 cam was used in PG car 235s starting in 1954.
