On a brand new rebuild (1990 302), I am leaking compression past the intake valve into the intake. Heads were reconditioned with valves and guides being ground. I observed this while rotating the engine by hand while tape was over the intake. I have two cylinders bleeding compression into the intake. I observed pushrods at the point of it bleeding off and both valves are completely closed when this happens. Should I be concerned, or will they seal up once it fires off the first time? Let me know if I need to take this up with the machine shop who built my heads.