Eric - Click on the Machining folder in the tree-view, in the list underneath find & expand the Stock entry - this gives you a place to set the stock dimensions & offset from zero. The nice thing about defining the stock is it automatically sets any machining ops to full depth (so if you're not going full depth.... don't forget to change them!). It also gives you a chance to see where to put any clamps or other hold downs.
Thanks David!
Thanks Ralph - hmm, chrome? Sounds expensive, I think I'll just paint it silver....
A quick update to report - it worked like a charm! The head popped off with no trouble at all, once I stuck some 200mm long bolts in it. Unfortunately, one of the bolts has bound up & won't screw or unscrew from the plate, even with the addition of plusgas. I'll try some heat over the weekend to see if that'll shift it. I can only assume the threads have gone wonky. For future head pulls, I think I'll turn up some rods to push through the holes, a couple of them are right on the edge of the head studs (due to measurement inaccuracy). As it happens, this head, once moving, only needed the outer edge bolts turning to easily pull it free, I've heard of some which fight all the way to the end of the studs, due to rust.
And the really good news? The head is in good order & so will deputise nicely for the damaged head from the original engine - and the pistons are the right type too, so I just need to free one of those and I've got a good set of parts ready for the rebuild! Just need to buy some new bearings, cams (I want race cams), tappet shims, valve springs, valves (going larger), valve seats. head & cam studs.... then I've got to machine the new valve seat recesses, port & polish the heads, give everything a really good clean up, throw it together & see if it works..... I can't wait!