I never got that kinda speed out of my 1.5T, so yes I'd say a different ratio rear or an different trans with an overdrive ratio, not sure what was available in the 60's .... depends on the engine too, if you've got a 283/327 they'll take the revs

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics