I ordered a new master cylinder for my 73 f350. Then I got reading about some had bendex casting and non bendex casting. If the brake lines are the same size threads will one replace the other? For what I see there really isn't much of a difference. But I don't want to affect my brakes either. Am I over thinking this ?

 

The MC for a '73 F350 would have a 1-1/4" bore. The primary port on the MC for the front brakes (port closest to the firewall) would be for a 3/8"-24 inverted flare nut fitting.

The secondary port for the rear brakes (port closest to the radiator) would be for a 9/16"-18 inverted flare nut fitting.

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