Just completed my first engine conversion to a k-jet + 5spd (big thanks to stu & loon for helping my out), but engine is making tapping noise (worse with acceleration).

2 questions:
My guess is its the tappets or hydraulic lifters, is this right?
If it is the tappets or lifters, whats the easiest fix? (do I need to replace all 8 or can they be repaired/refurbished etc..)