Brake master cyl. help
 

Howdy. I have a 1985 c20 and I need to replace the brake master cylinder. I got two from Napa and one from AutoZone. the problem is that the brake line fittings on mine are both the same size. I think they are 1/2 x 20. The ones They give me are different. The front one on the replacement ones bore is larger than my lines. Any help would be great .