My 69 B44VS keeps destroying push rods. They are getting shorter quickly. I pulled the rockerbox in October last year and replaced both pushrods. The exhaust one was fine but the inlet one was 1/16'' shorter. Now a few hundred miles later the inlet valve clearance is opening quickly.
Any ideas? Dodgy rods, cam followers?
I'd start at the top-end and work downwards to minimise dismantling...
Could there be excessive friction between the inlet rocker and the spindle shaft that it rotates on?
Wrong inlet valve spring - too high load?
Did the problem manifest recently, or is it long-term?