some info from an article in BDM #1:
The first models were available only
with a 105 hp 170 ci six cylinder
derived from Ford’s Falcon lineup. The
only available transmission was Ford’s
3.03 three speed manual with a column
mounted shifter. Transmission ratios
behind the six cylinder were: 3.41:1
first, 1.86:1 second,and 1:1 third. When
the 289 V8 option was introduced in
March 1966, the three speed manual
behind it had ratios of: 2.99:1 first, 1.46
second,and 1:1 third. The transfer case
was a Bronco specific Dana 20 with a
low range ratio of 2.46:1. Unique to the
models was a tall shifter with a shift
pattern matching that of the T-handle
shifter, but with a J- handle style ball
mounted on top. Most ‘66s also had rear
shock absorbers that angled forward in
front of the axle with stud mounts at the
top instead of the later rear-canted eye
mount shocks. The Bronco, with a 92
inch wheelbase was offered in wagon,
half cab, and roadster configurations.
The roadster option was not very popular
and was discontinued after 1968.
Standard brakes were 11 x 2” front
drums and 10 x 2.5” drums on the rear
on the small bearing(2780 lb.) axle and
11 x 1.75” drums on the large bearing(
3300 lb.) axle. All Broncos
employed a Ford 9” rear axle and until
1971, a Dana 30 front axle rated at
2,500 lb. Axle ratios were 3.50:1, 4.11:1
and 4.57:1(6 cyl. only). The standard
gas tank held 14.5 gallon with an
optional 11.5 gallon second tank available.
Options for ‘66 (including dealer
installed accessories) included: Warn
free wheeling hubs, snow plow kits,
winches, tachometers, Air Lift front
auxiliary springs, trailer hitches, tow
hooks, etc. Most of the options and
many others were included through the
Bronco’s twelve year run.
Production for the 1966 year totalled
18,200 units.
1967: The Sport Package was introduced
in 1967. This package included
bright finished horn ring, windshield
drip, head and taillamp bezels, side window
frames, instrument panel trim and
tailgate handle, cigar lighter, chromeplated
grille, bumpers and front guards,
red die cast F-O-R-D letters appliqued
to the grille, and 15” wheel covers. A
bright trimmed hardboard headlining
and vinyl floor mat were also added to
the Sport Wagon. A dual master cylinder
with a split hydraulic system and selfadjusting
brakes was also new.
Back-up lights were now standard and
an 11.5 gallon auxiliary fuel tank option
was available.
16,100 Broncos were built in 1967.