Thunderbucket, if you cut and paste the following query in to eBay's search field, there is always disk brake conversion kits listed:

(61, 62, 63) (thunderbird, t-bird, tbird)

Also, I've heard that the spindles and brakes from a 66 bird will bolt right into a bullet bird front end. 66's came with front disc.

I have a 63 that just get a suspension face lift. The next project for this money sponge is a complete paint and body resto. $5,000!! Interior is complete, engine is complete though I'm not satisfied with the performance from the stock 390.