The Fuller RTX Roadranger was probably the ultimate 9-sp 'box. So here’s an idle thought for a Sunday evening. Given that some ERF NGCs lasted even unto the late '80s, were any of them ever gearbox-upgraded to the later Fuller RTX 11609, as fitted to C-series and E-series ERFs? That would have been some mean machine!
Or to take the issue (fantasy, really) a tad further, if an NGC were re-engined with a ■■■■■■■ 350 (and we know that at least one was), could it easily be re-gearboxed with an RTX 14609 as fitted to some E-series ERFs with ■■■■■■■ 400 engines. I doubt if it would be rocket science to do so.