Still no news on spring pressure, if it were zero you would not have failed the cam. If it were 1000 lbs well you have your answer.
As far as roller lifters, beleive it or not one of the best is the cheapest, ford racing. I have seen comp cam lifters will the roller is not wide enough and you can see the needle bearings, I have seen comp cam lifter with bad metering plates that were concave and would not pump
oil up the push rod. I have seen comp cams with sheet from a new lifter inside. Comp cam lifters are sheet.
After talking to numerous builders the cause of hydraulic roller lifter failure is usually a result of too little spring pressure, where the rollers are slamming into the camshaft.
When you look at the Ford hydraulic lifter, you have to remember Ford trust them in milliions of cars and warrants them. They also buy in HUGE HUGE quantities. So you load it up with heavier spring pressure as compared to stock, ok, it last 100K miles instead of 200K miles.
As far as lubrication,
oil pours into the lifter bore to pump up the lifter but it also overflows direclty on the lifter wheel. Next time you have your manifold off prime the
oil system and watch what happens, oil flood everywhere.
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