Advice vs pros and cons of engine flush

The 318 in my 78 fury ticks for a few secs when I first start it, an original 56k mile car.
I have had the intake and valve covers off, it's very clean inside. It's only a few seconds, and it has usually sat anywhere from a month to 6 months when it happens. It's only a few seconds, and if I start it more regularly like in warmer months when I'm more likely to be driving it sorta regularly it doesn't tick when I start it. I do have a cam n lifters here that I want to swap in ( mild upgrade) for the hell of it this winter. .. new but 25+ years old Mopar performance lifters....