1978 rotors info

[DG racing]

ok what is the exact difference beetween 1978 front rotor and 1979 and up rotor ?

 

[Doober]

Bearing size is the difference.
Got these part #s from Rock Auto.

1978
NATIONAL Part # A2 {Taper Bearing Set; Cone Length=0.475" Bore=0.75" Outer Diameter=1.781" Width=0.61 StoundOut=0.135" Cup Length=0.475" Cone Radius=1.046"} - Outer
NATIONAL Part # A6 {Taper Bearing Set; Cone Length=0.465" Bore=1.25" Outer Diameter=2.328" Width=0.625 StoundOut=0.16" Cup Length=0.465"} - Inner

1979+
NATIONAL Part # A3 {Taper Bearing Set; Cone Length=0.55" Bore=0.8437" Outer Diameter=1.9687" Width=0.69 StoundOut=0.14" Cup Length=0.55" Cone Radius=1.046"} - Outer
NATIONAL Part # A6 {Taper Bearing Set; Cone Length=0.465" Bore=1.25" Outer Diameter=2.328" Width=0.625 StoundOut=0.16" Cup Length=0.465"} - Inner

 

[DOUG213XRJ]

ok what is the exact difference beetween 1978 front rotor and 1979 and up rotor ?

The spindles are also different 0n a 1978 G-body.

 

[DG racing]

thanks so i just look on my car and its A-2 bearing so its a real 1978 spindle

so i think i will install drop spindle of s-10 so after it will be easy its the same rotors as a 1982/83 malibu and s-10 82 /95

 

[Doober]

More bearing surface too