LIke many things today, some companies are selling 351W seals that will sort-of-fit a 351C. One is a low-drag teflon one-piece seal. Takes special installation technique (NO oil or lube) and you need to bore the back end of the block/rear main cap to fit. It will fit an altered Cleveland but there are easier, cheaper ways to fix a rear main seal leak....
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.