[V8] tick tick tick

[MORRALEE David]

1993 V8 high kms
 
On start up the car is fine no ticking from the lifter (s) .... then
after about 4-5 mins I get a tick coming from one of the heads . Now the
tick isn't horrific by any means . On start up the oil is cold so it is
still viscose , but when it warms up the viscosity of the oil becomes
less. 
I'm just starting on the t-belt change / installing the new trans and
will eventually take the heads off to replace the head gaskets and Valve
seals . 
 
Has anyone had this problem before with a ticking hydraulic lifter ? I'm
thinking I could go to a higher viscosity oil or warm the engine up and
do a press down test on the lifter themselves to find the bad one ...
then replace . what are your thoughts ? 
 
superdave