What oil are you running in this engine?
All flat tappet cams need a zinc additive present in the oil or it will only be a matter of time before a lifter / cam lobe will chew itself to death.
I use Valvoline VR1 in all my flat cam engines....
How ya doing mate? An Aussie here in Cherryville NC USA. Been here 20 years now....retired now but still active in my trucks etc. If ya need any parts I may be able to assist locating some...freight will be a bomb, but I dont think there are that many Square Bodies downunder....anyhoo....have a...