junkyard engine, sluggish

I picked up an 80k engine from a local junkyard to replace the previous one that died from the infamous coolant leak. after i got it in and everything hooked up it had a lot of top end noise. i replaced the oil pump with a working unit but there is still a small portion of the noise around. also, sometimes on acceleration from a dead stop it just doesnt have the nads it normally does. makes plenty of noise from the engine but while i push the pedal down the noise and engine speed slowly move up. kind of a dead spot. any idea's on what to look at? i have a feeling that maybe a lifter or two has yet to get pumped up but dont know if that would be the cause of having a doggy car. tia

Did you inspect the upper intake in the replacement engine for signs of the same leak? Did you change plugs, wires, PCV, etc...? Have you inspected the oil for contaminants or metal particles? Give us a little more info please.

the upper intake looked to be in decent condition, however, after the recent spat of problems i replaced it with a delphi unit. new plugs, pcv, iac, ckps and changed the oil three times due to the replaced oil pump and then just because. doesnt appear to be anything foreign in the oil that i can tell. sorry about the wait, i posted yesterday and caught it just as site maintenance started.

From what you describe, it could be a lifter still sticking a tad and not "pumping up". There's a chance that the lifter is collapsed, or a worn cam lobe could be causing your tick, but unlikely (unless this engine had a plenum leak and the bearings got washed with coolant).