Mark - you are absolutely right. Those are the same heads on an iron block in your link.
As far as I know the de Tomaso P70 had an all aluminum engine and this may have been the engine in the de Tomaso Museum, but the Sport 5000 showed up in California a couple of years ago with these heads on an iron block engine. I am still getting upload failures on the photos even though they are all within the acceptable .jpg size limits. But if you click on the links below you should be able to view them in my Photobucket album. These photos show my all aluminum engine ca 1978/79. It certainly looks all the business! I spoke with Pete Brock about this a few years ago and he remembered the all aluminum engines from his work on the P70.
What I am trying to discover is whether this was the same or similar block as 1963 Ford Indy pushrod engine with the four transverse mounted Weber 48 IDAs as driven by Dan Gurney. I am also interested in finding information on the XHP 260 aluminum blocks and the 289 aluminum blocks.
http://i470.photobucket.com/albums/r...f.jpg~original
http://i470.photobucket.com/albums/r...a.jpg~original
http://i470.photobucket.com/albums/r...3.jpg~original