They can be sleeved with stainless. Why not? Why will a new cast iron unit last longer than a rebuilt one?
Precision Proformance (Byers) has them too.
http://www.precisionproformance.com/bc3001.php
$159.
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.