[bowtieguy]

if you use a conventional oil then yes slick 50 or another additive like it is worth it, if your engine is still running great.i personally use a synthetic oil so slick 50 would be redundant.all i was getting at and sorry about any confusion is if your engine is worn then no additive is going to make it run like new for long.in the case of a sticking lifter yes there are tricks to temporarily fix the problem but in the long run to fix it replace it.