1986 2.9 flat tappet?

[RangerGoolz]

I have looked online and found conflicting info but am I correct that my 1986 2.9 has a flat tappet cam and hydraulic lifters? I had been using mobile 1 10w40 and recently changed to Brad Penn simi-synthetic 10w40. I did this for the extra zinc in the Brad Penn. Any thoughts on this oil? Engine is in great shape at 115k miles and has a very slight leak at rear main which I plan on having fixed very soon.

 

[Shran]

You are correct about the cam and lifters.

Dunno what to suggest for oil. The extra zinc for sure will not be a bad thing! Just spendy. I have read that zinc additives don't do much because they don't fully blend with the oil so if that's true, your plan of attack makes more sense.

I have just always run whatever is cheap in my engines, except my V10 (that gets full synthetic 5w20.) No premature failures yet. I know PJ had some issues with a cam coming apart on his 2.9 and blamed it on low zinc Mobil 1. He knows his engines really well and that could very well be true but I would like to see some sort of scientific analysis that proves that the oil caused the problem... and not contaminants from something else or just a straight up worn out engine.