I recently bought a 75 el camino with the 350 in it. it needs tons of work and i'm on a limited budget... anyway, i took off the valve covers and decided i was going to clean up the rockers and pushrods. being the amatuer mechanic i am, i didnt look to see how many threads were showing on the studs the rockers are on or anything of that sort. after installing them, i realized all the valves were at differant heights. this makes sense obviously but how do you know how much to tighten the bolts down? specific torque? as of now they are all just loose enough so you can just barely move the rocker or the rod. what to do? also upon installin new valve cover gaskets, do i need some silicon? i got rubber ones not cork.