If the OP was planning to install the MKII in his A3000, and DID NOT have the CyberSCSI module on his CSMKII 060 card then NO Int2 Mod needs to be done! ;-) But he was asking about the A3640 card. This card can be made to work on the A3000, but AFAIK the A3000 needs all the latest chips. Try Google.
