Heavy duty suspension was an option regardless of
engine, but torsion bar size depended upon body style, engine size (6 or 8,
don't think there was a distinction between 318 or 361 except for factory
settings of the ride height means higher initial resistance of t-bars for the
heavier engine) and whether standard or HD suspension. Guess we all have
to crawl under the cars with calipers and report what we've got after the
grime and extra paint is removed. Would be an intersting data list. Rear
springs are a different subject, it was not exclusively engine size making the
difference. Ever hear of Constant-Level air suspension on the '59's? Those
cars had FOUR leaves only, air bag made up the difference. I've seen one in
person, about 35 years ago. Told you at the outset that I had some real
stories about these buggys - and they're all true!
12 inch brakes were a separate option, again, a
heavy-duty feature. There was a mid-year (Jan-Mar, not exactly sure
when) change in style of backing plates, as to the stamped platforms that
support the brake shoe, probably for quieter operation.