Toyota Repair: 90 4runner engine noise 3.0 v6, cam bearings, train noise

Question
i have a 3.0 in my shop with what sounds like vavle train noise. a tick that increases with rpm changes. i have the valve covers off and and all the shims are still in place. the biggest variance in valve lash is only .003. the noise doesnt sound deep enough to be lower in the engine. any prior repair experience that might save time and labor? my next step is to pull both cams and mike all lobes and check springs etc.i have no prior exp. with this engine  

Answer
There are two things that I thought of right away, either a broken valve spring or a piston noise, remove the camshafts and check the cam journals and the contact surfaces in the head, there are no cam bearings, with the cams removed push on each valve shim if any are real easy to push down inspect that spring, the other possibility may be a piston problem or wristpin problem, especially if the noise goes away after the engine warms up.