That amount of end play is a bit beyond the suggested max. Don't hold me to this as I am not near my reference manuals but I think I recall over .012 is a problem. I will check my info and edit the post if I am wrong.
I am not sure if this condition actually contributes to "pumping oil" but I have heard or read that it will. I do not remember the source of the theory about pumping so I can not give a "for sure" answer.
With new engines, I hold the end play between .003 and .005 and use bronze thrusts front and rear with insert bearings.
The combination thrust and seal works quite well. My concern is that if the wear on your thrust surface is mostly on the front, the combination bronze thrust and seal may not be enough to take up the excessive end play. The part I am describing is shown below. I lifted this pic. from Snyder's. The combination thrust and seal needs to be set in a sealant when installed in the block. Completely bedded in sealant is the best way to avoid leaks. When placed in the block make sure the ends do not protrude above the block as they would keep the cap from fully seating to the block. Dry fit the part first and file the ends if they protrude.
To properly install this component it would be best to remove your engine from the car. It could be done in the car, but oh my, that's a lot of work laying on your back if you do not have a lift.
Good Day!
Dave in MN
www.durableperformance.net
Rear Main Thrust
This bronze thrust washer replaces the original A-6335 reara main seal that went up in the block. If the babbit on your old rear main bearing has cracked, this will now act as your thrust. ...
Part NumberSpecificsPrice A-63341928-31$39.95 / ea