85-88 -- 266/266 at .006" Peak lift of .444" w/1.6's Ford doesn't list .050" durations, and they vary quite a bit based on people who have measured - from 208-219. I believe LSA is 115.
89-95 276/266 at .006" Peak lift of .444" w/1.6's; I believe LSA is 115.5. Despite the greater .006" duration on the intake side, .050" lifts remain similar for both cams. The ramp rate was reduced in an attempt to quiet the valve train on the intake side. The earlier cam is considered the one to go with -- Ford lists it as capable of making about 3HP more than the later cam all else equal.
There's no such thing as 'lift at .050" '. Well, I guess the answer is the lift at .050" IS .050".
As I said - you have to measure YOUR cam to see what the durations actually are -- notwithstanding the brand promise at the time, quality was not job 1 when those cams were being made.
Therein lies the challenge with degreeing the stock cam -- unless you know what the specs of your cam are, it may not make sense to use the factory valve events to degree it with. The specs call for the .006" lift Intake Open to occur at 20 degrees BTDC. That's as good a place as any. If you're really wanting to get the most out of it -- I'd measure up the cam -- and then hire Buddy Rawls or one of the cam designers to model your set up with the specs of that cam and let them tell you where to install it for best effect.