We already produce the Clejan Spine Cars www.nscalekits.com the G-85 cars were used more widely than the Clejan cars, since although the G-85 cars were capable of clejan use. The General American built G-85 were used by the SP in Classes F-70-14 and F-70-15 [Tony Thompson points out that the similar R-85 cars were not bought by SP but converted their R-70-18 cars into similar cars in 1962]
I think you maybe mistaken Peter. Here is some info directly from SP engineering files and a contact in GATC.
F-70-14 : GATC class R-85 w/ Clejan loaders w/o side handrails purchased in 1959, converted to bi/tri level autoracks in late 1960 using W&K frames
F-70-15 : GATC class G-85 purchased in 1960, no Clejan capabilities
F-70-18 : GATC class C-85 purchased in 1960, sent back and rebuilt by GATC in early 1961 to G-85 (renumbered too)
F-70-19 : GATC class R-85 purchased in 1960 from New Haven (built in 1958), converted to bi/tri level autoracks in 1961 using W&K frames
F-70-22 : GATC class G-85 purchased in 1961, no Clejan capabilities
F-70-24 : GATC class G-85 purchased in 1962/3, no Clejan capabilities