new raleigh headset
 

where can I get a new 26tpi headset for my '72 Raleigh Grand Prix?

1" x 26tpi headsets have been deprecated for several decades already. They are still made and used in southern Asia; perhaps a mail-order place in India might be able to sell you one?

Otherwise, you will need to salvage a used one from another bike.

Yeah, unfortunately its either find a headset off another bike or ebay. The only other viable option would be to get a new fork and use a standard headset.

if the top portion of your headset is still good you can reuse it with new bottom bits

Excellent suggestion. Typically the top race and cup last forever unless they are rusted from water damage. The lower cup and crown race take the beating and are almost always the only damaged part.