Do a search on recent threads. I saw a post where a Cruiserhead replaced his smog pump with a one wire GM alternator and ran two alts and batteries. Said GM part was a bolt in......
Front Heater Core FJ60
Spectre has new and used heater cores in stock.
http://www.sor.com/sor/products2.tam?xax=24250&pagenumber%2Eptx=1&category%2Ectx=188%2D26&pagenumber%2Eptx=1&page%23%2Ectx=188