I think on some later distibutors it is attached to the side, but where it's separate it wlll probably be wired between the distributor and the coil.

"Y mae dafad ddu ym mhob praidd"
1972 4/4, 1981 MGBGT, 1984 FLHT1340, 1980 XLH1000, 1990 ZX10