I have a 94 ranger 4.0 I noticed the spark plugs are turning white haynes man says could be intake manifold vac leaks I see gasket problems are common so im just gonna change them for giggles it also has the 4.0 famous tick can I fix this by changing pushrods??

 

If you have such a leak in the intake manifold as to cause the spark plugs to go white, the engine would be running badly. And you would trigger a check engine light from the engine computer.

I hear that the ticking noise is from the rocker arm wear due to insufficient lubrication getting to the tip area. The difference in length is very small, so I don't know if you can get pushrods in such small incremental differences.

I seem to recall that the old Cologne engines may have adjustable cups in the rocker arms, but I don't know if the more recent versions have them.