Kelsey Hayes disk brake conversion question

You are also going to need some new parts. I am attaching a link to one source, but I am not recommending you buy from these guys -- they are very expensive. But they do show good photos and descriptions.

https://www.jimsautoparts.com/brake.htm

There is a foam gasket between the spindle and the splash shield - BR-339 on this page. There is another gasket between the master cylinder and the firewall - BR-477. The master cylinder you want will look like BR-1152 at the top of the listing, but there are different versions depending if you have power brakes or not. You can also choose to use a specific bore size master cylinder to change the pedal effort required.

You might also need to buy the rubber boot for the master cylinder pushrod - KQ-BB1

Don't forget to replace the rubber flex hoses. Do not trust old used ones even if they look "OK".

I suspect used calipers are not going to be fully functional, especially for the price you paid. Make sure all pistons are loose and sliding in the bores. If they are not, order replacements and turn those in as cores.

You will want to check the disks for thickness and whether they are heavily grooved, and probably have them turned. You will want to repack the bearings (at least) or replace them.

The easiest metering block to use would be the one with the built-in proportioning valve -- it saves buying and fitting an external proportioning valve. Here is a link: http://www.classicindustries.com/product/mopar/parts/md2268.html

You will need new hard lines between the master cylinder and the metering block -- these are available from Fine Lines and other places. But because you need lines for a dual system, you can't buy them for a 1964 Dart. Dual lines became standard in 1967. So the ones for a 1967 Dart with disc brakes should be usable, but will probably need to be bent to fit.

I just did this conversion on a 67 Barracuda. Your task is slightly more complicated because you only have a single line system in your 64.