Both Boomslang and Rywire make conversion harnesses for obd2b automatic to obd1, according to rywire you need obd1 ecu, tcu and dizzy, according to boomslang you need obd1 ecu,tcu and transmission. There is a guy that has done the obd2a auto conversion, it worked for him, and he used crome, see articles here:
http://www.accordinglydone.com/forum/showthread.php?t=12424, and here:
http://www.accordinglydone.com/forum/showthread.php?t=10550&page=2. Now I am not opposed to using an piggyback, that is something I need to look more into, so far it seems like it is more expensive, but much easier.