1961 - 1964
Complicated type tachometer sending unit eliminated in 1964.
Lower and upper "A" frame used identical rubber bushings mounted with clamps. Easier to change than improvement made in late 1964. Lower "A" frame had tendency to crack behind ball joint. "A" frame changed in 1964 to stronger mount. Pressed fit bushings used with this modification from 1964 on.
Front shock mounting plates had one bolt, late 1964 - 1973 cars have stronger setup with two bolts.
Body floor pan dimensions were changed at serial no. 16.499 (VOLVO drawing no. 101728) which was a 1964 model. Floor pan dimensions are identical from serial no. 16.500 on (VOLVO drawing no. 102099). Reference: Body Structure manual TP10268/1A.
1961 - 1965
Traction rods on rear suspension had single arms held to rear axle with clamps not as strong as later torque rod arrangement.
Radiators have large top tank with overflow outlet tube and low pressure cap. Top radiator hose odd shape and hard to find.
Cars had separate intake and exhaust manifolds with S.U. carburetors.
Exhaust had single 1 3/4" head pipe with two mufflers.
1961 - 1966
Drive shaft mounts and carrier assembled with fingers that slide into rubber. Much easier to remove than later models. In 1966 - 69 models, bolts must be removed to drop drive line. Much more difficult than earlier cars.
1965 - 1966
Oversize torque rod bushes used on rear suspension — not compatible with earlier or later cars - used one year only.
1965 - 1973
Rear suspension used dual torque rod arrangement with metal sleeved bushings. Bushings develop "cracking" noise when dry.
1966 - 1967
Intake and exhaust manifolds were one piece with dual outlets.
1966 - 1973
Radiator has smaller top tank and overflow catch bottle. This is the best system, but it can have vacuum leak, lose coolant and still appear to be full. Rubber seal in radiator cap collapses from heat. This radiator can be converted to earlier cars as mounts, brackets, etc. are identical. Thermostat housing will need to be changed along with hoses.
1967 - 1971
Heavier drive shaft added with large flanges. 1972 - 1973 models have lighter drive shaft with smaller flanges.
1968 - 1969
A transmission flange appears on these cars - large flywheel type.
One piece manifold with pre-heating chamber added. Stromberg carburetor used. Extremely hard starting when hot.
1970 - 1971
Gearbox M 410, used one year only
1970 - 1973
Rubber center support spring added.
Fuel injection added with separate intake and exhaust manifolds.
Exhaust enlarged to 2" diameter with three mufflers.