need advice

I purchased a 350 crate engine with 202 heads this motor was fresh but set in my garage for several months before installing - I cranked it on a regular basis - I had a motor stand set up with a radiator - After finally installing in my 49 ford it has been running like crap - When it warms up it starts tapping on one of the lifters - We already set the lifters after warming the engine and still taps and bangs out after it warms up - The comp mild cam was new when engine was done - This was a oreilly crate engine and the person i bought it from had the 202 heads done for the motor and installed the comp cam ..

Did you break it in @ 2000 rpm for 20 min.'s??

Best guess.......
You either have a soft lobe on the cam or one of the rocker studs is pulling out of the head.
Pull the valve cover and lay a straightedge on the top of the studs. If one of them is pulling out, you'll be able to see it.

is it hydrolic or solid?? if its hydrolic id say you have a lifter bleeding down,,,just find out which one and replace it,or buy a new set and try that,,if its solid your gonna hear some rocker arm noise,,,,how much oil pressure does it have??? it could also be the oil pump going bad
Allen