Hughes "retro fit" lifter not pumping up!

Do your lifter internals consist of the following...Lock clip, Push rod cup, Plunger, Check ball, Check ball spring, Check Ball retainer and last the plunger spring?
Not much that can go wrong in there other than the already stated debris keeping the ball from seating properly. Are your push rods oil through or solid? Obvious conclusion other than debris would be a burr on the ball seat or excessive machining clearances causing bind or leak down or tight machining clearance causing bind...perhaps scoring or galling causing bind. Don't know what the tolerances are but I would suspect a near wipe fit between the bore and plunger. My guess would be an issue in the check ball retainer machining not allowing the ball to move away from the seat if you cant blow air through it like the "good one" but all the check ball is supposed to do is allow oil into the pressure chamber when the valve is closed. Never had one of these apart...if it's got a check disc the principal of operation is the same. I would swap the retainer and ball from the bad one to the good one and see if the problem follows the parts. if it doesn't, the next thing I would swap is the plunger. Like mentioned above, if it's a disc...check orientation. I don't know, either the check valve system isn't allowing oil into the pressure chamber or isn't closing completely to retain pressure in the chamber or the metered bleed back between the bore and plunger back to the reservoir clearance is too large not allowing pressure to be retained in the lower pressure chamber.
I'm about to get mine going with the same cam and lifters...wish me luck.