Spark plugs: 7 tan, 1 black

[vettestr]

The advise to install new seals can't hurt by any means. You could remove 1 spring and then release air pressure (with a firm grip one that valve) and check the side to side clearance between guide and valve stem. Then replace the seal with the umbrella type if you are not already running them. Do install new locks even with the minimal miles on old locks.
Repeat the above steps on second valve. This way you can verify the clearances of the valve to guide and new umbrella seals installed for a piece of mind.
Just my 2 cents here and some would question if even worth 2 cents but here goes. I do not think a seal even if it is missing with proper V to Guide clearance will give you these problems. A bad guide would and a seal will not repair or compensate enough to matter. If the guides are good then she is sucking oil through a gasket or porosity or even too aggressive porting but a hole of some type. Hooking an air hose with 150 psi up to that cyl. and the rockers backed off might allow you to see or hear were the air is leaking. A slim chance or 50/50 at best you would see where leaking as you can only see so much but you are there with air to do seal change anyway. Plus the air left on for a bit will blow the rings dry allowing a second test on that hole for a dry compression test.
Might think about just keeping extra plugs in the car and driving it until problem gets bad enough to force deeper dis-assembly and repair costs .