FWIW, Ford says the big distributor caps are to reduce cross-firing both inside and outside the cap, and being vented (the odd protrudence between wire towers and coil) reduces ozone that's produced inside the cap from rotor sparking. Finally, big caps only take modern sparkplug ends due to the male-type cap connectors. Ford also once produced weatherproof rubber distributor boots for boats and cars with semi-exposed dizzy caps- but they only fit the big caps. Boots are nice for Panteras that are driven in bad weather.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.