leaking windshield

The windshield leak has stopped with all your advice. Thanks I have a new problem i am collecting oil on top of the intake manifold by the bolt holes that hold it down. Ive had some problems with head bolts on some Chevys that had to be siliconed to stop antifreeze from leeking in because some of the bolt holes went into the water jackets. Im going to pull one of the bolts out to check and see if the hole goes all the way threw the block so oil can get up the bolt. Does any body have any info about the intake bolts on a 1970 340. Do all the bolts need to be wrapped in siliconed? Thanks Stony