Use the IGN3 connection with a fuse
I just finished installing my Knock gauge last night and I found that the connection labeled IGN3 in the fuse block is not powered during cranking. It is near the center of the fuse block. I just put a tab on the end of the wire and inserted into the IGN3 connection. I don't know if the IGN3 connection is fused or not so I would install a fuse in the wire right after the connection with the fuse block.
The IGN1 connections are powered during cranking and should NOT be used for the knock gauge.
HTH
David
87GN