would a spare head with the same valves and cams & rocker arms have the same (or very close) v2v clearance?

I've been stressing my v2v clearances (probably needlessly) and I've found a friend has a spare head sitting around, the same head as mine, with the same stock valves. If I borrow this head and put my cams w/ adjustable gears in it, would it be reasonable to use this spare head to measure v2v clearances and although they wont' be precisely the same it should be close enough? As far as I can figure the things that affect v2v clearance are the valve seat if there's been a valve job, the valves themselves, the cams & rocker arms. With my head vs the borrowed head all would be same except possibly the valve seats of the borrowed head if they've had work done before (unknown).

I don't expect my clearances to be super tight so I think precision to .001 isn't necessary, and that aside I find the process of checking v2v something that isn't really at that level of precision anyway given it depends how you slide the feeler between the valves.

As you figured out, the position of the valve in the head will affect it's relationship with the piston, but one factor you missed is how much material has been removed from the cylinder heads.

You could check your head's clearances, and then compare it to the borrowed head, but that would be a bit redundant.

You do seem to be looking at ways to make a relatively simple job rather difficult... Perhaps you would feel more comfortable practicing on the other person's long block before doing your own engine, as a compromise?

Re: your 'zero lash' post, technically that isn't 'lash', but contact and so cannot be set - at best it will be a degree of applied force. Depending on application, you may find something like 0 +0.001 - that said, with hydraulic type lifters/followers don't actually have 'lash' and are commonly referred to as zero, N/A, "0", etc - is that what's confusing you?

My reticence to pulling my own head to check these clearances is for a few reasons. It will cost me a $100 head gasket (I use mostly OE stuff), another $40 or so in other gaskets for the headers and intake manifold, another $40 in replacement coolant, and then there's the risk of all the things that go wrong in the process (broken or stuck bolts, could screw up placing the head back on and scratch the mating surface, etc...), and then there's the inevitable coolant and oil mess I'll have to clean up in the garage and engine bay. This would also save a ton of time as it would probably take me a full day to remove and do this with my own head, and that's if nothing breaks causing me to wait another week or 2 for the replacement nut or bolt to come in the mail (you know how it goes) and I've gotta value my time at something. Something about Murphy's law. And yes I do also like the idea of practicing on the spare head too for these same reasons.

So if I have a spare head that is more or less the same it seems potentially a good way to go. That's why I'm looking for some validation here of this concept here. I can do the v2p clearances on my own head with the check springs without removing the head.

I'm not clear though on how milling of either head would affect v2v clearances? I would think that would only affect v2p no? For the sake of this thread I'm only interested in v2v and if a spare head with my cams in it and the same stock valves would be similar enough for this purpose.

Ah, me bad - you're correct, it would only apply to V2P, usually that's the concern and I had a 'senior' moment - AKA brain-fart...

Ha, no worries. Thanks for that, sounds like the idea should work well enough then.