Smokin Fuses

I have a 74 Z1 been sitting since 1994. was told ran when parked. I threw in a battery and tried to fire it up. It turned over but then smoked the fuse. I checked cleaned added new fuse. Tried it again this time Starter relay clicks and the white wire from the retifier to the fuse starts to smoke and blows fuse,this when pressing the start button,of couse
I know this will be a real brain buster any thougths where to look first?
thanks

I'd go through the harness connection by connection, make sure they're all clean and tight. Would also give you the chance to check for any obviously bad wires.

Also, shine the clips on the fuse block real bright, that'll make sure you don't have any corrosion creating resistance on your fuses.