Welcome aboard juggernaught, :t:
.0005 on a ring is too tight (I can't even measure that close!!). Under temps the rings expand and press against each other which could result in breakage.
What's been reccomended by blueprinters is something close to a Piston-to-Bore: 0.0018-0.0021" and piston ring endgaps of: 1st: 0.021-0.024 and 2nd: 0.025-0.027.
However, different type rings expand differently, what's the spec sheet say?
It's not uncommon to have rebuilt heads. What needs to happen is measure the pushrod length - either you or the shop - to ensure the length & geometry is correct (wear point dead center on the valve stem). My guess on the 'washers' is they were used to bring spring pressures (spring load) up to specs, but not knowing what year or engine you have, this is what's listed as "stock" for a V-8:
360 = 85-93#@[deleted].812" (spring height)
390 = 90-98#@[deleted].812"
401 = 90-98#@[deleted].812"
If you're going to a performance cam, stock spring loads are usually too light so look at the cam sheet and see what's recommended. I think mine are 110# springs on a Summit hydraulic flat tappet, but a good shop could also give you a recommendation.
