First, it sounds like your lifters have no oil in them so you need to soak them in some oil first before you install them. Once you install them, pour more oil in on the, take a push rod and pump the lifter to get the oil inside the lifter. You should feel the lifter fill with oil and get stiff.
Next, the push rods and rocker arms, fulcrum seat oil deflector and bolt must be installed and tightend in a certain order as follows;
Postion the No. 1 cylinder at TDC on the compression stroke and tighten the following valves:
#1 intake and #1 exhaust
#4 intake and #3 exhaust
#8 intake and #7 exhaust
Rotate crankshaft 189 degrees and tightend the follow valves:
#3 intake and #2 exhaust
#7 intake and #6 exhaust
Rotate crankshaft 270 degrees and tighten the follow valves:
#2 intake and #4 exhaust
#5 intake and #5 exhaust
#6 intake and #8 exhaust
Make sure you put some white lithium grease on the tips of the rocker arms and valve stems to **** everything untill the oil pressure comes up when you start the engine. If possible, pre-**** the engine by turning the oil pump with and electric drill and pre-oil shaft (most auto parts stores will have them-about $10.00). Run drill till you see oil flow at tops of push rods. Remember, oil the **** out of everything, too much is good, too little can really cramp your day.