$1500 is a low price for an 87, how's the paint, interior, wheels/tires, does it blow any smoke when it starts or during acceleration.
where it sits are there any leaks.
how long ago the belts/waterpump were done.
let it run for 10 min and see if the clicking goes away.
get a ppi inspection, well worth the investment to evaluate the whole car and you'll know what it needs and if the guys lying about the valve, which he probably is.
if it won't run smoothly it probably won't pass emissions.
