KH SBP caliper sticking- best option?

Couple of ideas you can consider. First, you could PM hemi71x, as he has been an invaluable resource for KH 4 piston parts for this forum. He at one time had a series of contacts that could rebuild your calipers, and upgrade to stainless steel sleeves for the piston bores. Also, he sells (or he may be closing out his parts reselling side soon) rebuilt KH calipers and complete setups. His work is highest quality - bar none. He is however located in California so keep in mind that shipping might cost substantial $$$.

See the following For Sale thread = [FOR SALE] - **REBUILT** Kelsey Hayes 4 Piston Disc Brake Calipers 65-72 A Body Cars

Another idea = Rock Auto. Or you could buy the piston seal kits and simply hone the sleeves?

I think your best bet is reaching out to hemi71x via PM and he can give good insight to your best options.

Finally, use the search option in this forum for KH calipers and pay attention to hemi71x posts as well as the posts about caliper rebuilding parts and sources.