Yea, it gets more noticeable as it warms up..

 

I put a lot of thought and readj. my pushrods 2 or three times to no avail after the install. Read where some come out quiet and some noisy. The lash on my drive gear was within spec but I bet was on the loose end of the spectrum. He could have maybe used the oversize gear and it would run quiet. Or as Dawg said the rocker boxes could need adj. and as the motor grows with heat the tolerances change and the pushrods make slight contact making the noise. Mine runs great and I've heard others that sound just like it so I no longer worry. Those are some options you may explore or like many others get used to it and ride the hell out of it. My 2 cents.

 

A few yrs ago I did a 95 in build with andrews 26 cams and mild headwork.And with the cams you will hear more.I also had a tick,tried adjusting lifters a few times to no avail.Anyways after awhile,I had a lifter bleeding down,noisy on startup.Changed lifter and sounds great.By the way,all lifters were changed at build,so I had a defective new lifter.