I assumed that they came from the factory with offset keys installed for precise cam timing. According to Beagle's post that is correct and so knowing to what extent the cam timing has been adjusted by offset keys would require documentation or clairvoyance. Thanks for the links.
I had previously read the chain stretch DIY article. I have not yet checked the cam timing using a dial indicator, but given that the pump was out by 8° I would have assumed the cam out by more than that due to the fact that it is "later" on the chain. That the cam was out by 1/4 the amount I have to assume that the pump was set incorrectly or something other than chain stretch caused it to be so significantly retarded. There are quite a few things on the car that were done incorrectly (valve lash was more than 2X the gap on all intakes) and so the posibility of incorrect setting of the timing is not far fetched. Now having read Beagle's post I wonder how to actually measure chain stretch rather than the cam timing (which is what the dial indicator on the cam lobe will tell you).

Andrew