I am replacing the brake lines in my 67 coupe. What are the differences between the brake lines for a 6 cyl and an 8 cyl? The body is from a 6 cyl and the motor is a 351C. Which brake lines should I get?
The brake lines go with the drivetrain, in the sense that the V8 used a different rear axle housing than the I6. The I6 has the axle vent tube on the driver's side axle tube located about 2 inches more towards the center section of the rear axle. The V8 had the vent tube located 2 inches outboard, towards the wheel, compared to the I6. Since the vent tube is used to secure the rear distribution block to the axle tube, the location changes the size of the lines. This means you go with the I6 rear axle set.
Your brake lines might differ between 4 wheel drum and front disk, rear drum. This is because the 4 wheel drum used a dist. block w/o a proprotioning valve and the disk brakes set up used a different dist block that had a proportioning valve in it. The two blocks had different connection points, I believe, so that the front brake line set and the master cylinder to dist. block set are different, compared to the 4-wheel drum brake line set.
In summary, the engine size is used to give you the correct rear axle line set (in your case, the 351C is non-original so you have to go with the engine size original to the car, I6). The front drum versus front disk gives the correct master cylinder line set and the correct front brake line set. I believe the front to rear line is the same for all. Inline Tube or Classic Tube will have the skinny on this. You mght consider upgrading to stainless steel lines and braided stainless steel flex hoses, front and rear.