Thanks, Tom, but its gone several years ago. Wish I had known that at the time.
Ray there are good headers available, some better than this manifold because they have been designed without some of the compromises made necessary by cost, ease of maintenance and other mass production considerations...on the other hand most headers appear to be designed and produced with low cost of primary concern, not function. The poor quality ones typically have short primary tubes, tight turns close to the ports, thin and poorly aligned flanges and messy looking welds. Nearly all headers allow a lot of heat to escape close to the generator, which can't be good for its life expectancy, and close to the carbs.
I had one of these "not so good" headers on my car for a few years after the original cracked, but am happy to go back to cast iron!
Simon.