71 vs 73 disc brakes
Ok guys what is the difference in 71 and 73 A body disc brakes. Bolt pattern I know. Are the other other parts such as control arms and such interchangeable? I bought a 73 340 k member for my six cyl 73 Dart. I got LCA with it. I have access to a 71 dart with disc brakes for parts. Any thoughts. Thanks.
71 front clip looks amazing!!
Okay, front clip has nothing whatsoever to do with the OP's brake question.
Let's start at the beginning.
You're putting a '73 340 K member in a '73 Dart. I am assuming it is a drum/drum car, since you're looking to convert to discs. A '73 /6 Drum car should be small bolt pattern, and the following is based on that assumption.
Your disc brake parts source is a '71 Dart, also small bolt pattern.
Easiest recommendation is to use the rotors, spindles, calipers (and hoses), and lower balljoints from the '71 (upper and lower control arms should be the same for '71 and the above '73 application, varying only in swaybar mounting points or the lack thereof- but I'm trying to keep things simple here). Also use the '71 disc brake master cylinder and combination valve (and booster assembly if you're going with PDB).
Use your '73 upper and lower control arms, sway bar (if so equipped), tie rods, centerlink, idler arm, pitman and steering box (either power or manual), and strut rods with your '73 340 K frame. There are other combinations of parts that will work, but this is the most straightforward; and utilizes the most parts that you already have.
As an aside, if the '71 parts car is/was a V8, grab the torsion bars, too- they're heavier than your slant 6 units.