Got hold of a copy of the 1957 TriCor catalogue recently, and it contains some very rare birds indeed. At the bottom you can see a Delta Head for USD 103! This is the first documented evidence I have seen for this head as a stand alone accessory and it is shown with two left hand monoblocs fitted, probably wouldn't have thought that without seeing it.
If 103 bucks was too rich rich for your blood, how about CP162? A complete tacho kit, including the timing cover and the tacho itself for a smidge under 55 dollars!
Is it better to know this information, or is ignorance bliss?