If you followed everything the only part left would be one of two things I can think of:
Either you turned the engine over a lot and wiped off any break in lube on the surfaces priot to it firing and getting up to rpm (or it didn't fire immediately).
Or the lifter face was not contacting the lobe as designed because either the cam bore or lifter bores were not machined perfectly. It does happen. Any shop that has does lifter bore bushing will tell you the angles are off as much as the decks being high or head chambers being larger than factory spec. Personally I'm not a fan of going with a higher ratio rocker than the cam was designed for. Adding ratio makes it harder for the lifter to start lifting (lost leverage) and speeds up the rate of life for a given cam (it has to go further in the same amount of rotational degrees). Some manufacturers have special lobes for a higher ratio for that reason.
