This page was written by Ed King (The Nova Portal) and is used here at oldengine.org with his permission.
The following text and pictures were sent to the Nova mailing list by Pat Cossey, who gave me persmission to post them on this webpage. Thanks Pat!
This is what the wheel will look like with all the hardware removed, except the back plate which will be removed also. The two bolts at the bottom hold the steering arm in place and have nuts on the back side. The stud at the top where the springs attached will be unscrewed and the top mounting part sawed off to make a plain bolt out of it to go back on the disk set up. You will see this in another pic.
This is the hardest part to come by, a donor car is the best place to find them or Ebay about $80 for a pair is the going price. Oh yea this holds the caliper on , hence the name caliper bracket.
This is a shot of the spindle as I modified it, cut 1/2 inch of of top boss. Cut part is laying on rag. Notice my spindles are still attached to the ball joints, the steering arms will have to be unbolted to remove back plate as will show in other pics.
Here we see the dust plate and caliper installed after modiyfing the spindle in the first pic, the dust shields are avaliable after market but these came from a donor (65 Chevelle). Notice the top bolt with shoulder removed here!
This shows the rotor installed. Calipers from Auto Zone for 1971 Nova, $224 for the complete set up. Included pads and bolts for calipers. Need to see what the core charge was I didn`t have an exchange.
Here is the whole set up finished with the caliper installed. Now you need to consider the front brake lines will have to be replaced ,they are different than the drum lines. Cost me $85 for the pair. Maybe cheaper if you look around I didn`t shop on these items. Also the master cyl. will have to be changed to a disk brake master (Auto Zone $19.99 rebuilt). Old drum master has to much residual pressure for the disk they will stay to tight. I`ve been told that any GM prop. valve will work if you need one? So far mine seems to brake fine without one, altho I do have one off an S10 but that brings a problem in that the fittings are not the same so plumbing will be required. If you have any Questions just ask I`ll be glad to help. - Pat
...the drum brake spindle boss is around .610" taller than the disc brake spindle. If you shorten your drum brake spindle by .610" the disc components should fit. I don't have a drum brake spindle to measure so I can't verify that measurement.
Below you can see the upper bolt hole boss is between .400 to .480" SHORTER than the lower mount.holes. I have two spindles and one is .400" and the other is .480" . The hole size is the same as a drum spindle, and the threads start at the face of the upper mount.
This is a factory 67-69 disc brake spindle.
A drum brake spindle has a longer upper boss. On the drum brake application the hole is used for a brake shoe anchor pin.
THAT'S THE ONLY DIFFERENCE BETWEEN DISC AND DRUM BRAKE SPINDLES!
Photo shows the threads a little. If you have a drum brake spindle , you can cut the upper mount down..., and you are set!
Photo below shows a drum brake spindle-right, and a disc brake spindle-left.
Find more drum-to-disc conversion information by following the links in the "Tech" section of the Nova portal