whats the differance in a gsr obd1 and obd2 block

[honda801]

i im trying to find obd2 gsr block but keep coming across good deals on obd1 will this work and if not whats the differance between the two?

 

[honda801]

i know a little bit about it but i just want to make sure if i buy obd1 block im not going to have to add or change anything about my harness or ecu (once was enough)

 

[honda801]

what about ls blocks thier even cheaper whats the differance in b18c and b18b

 

[honda801]

ok, well i will try the obd1 block and see how it goes i will repost and tell you how it goes thaks