update .got them out !
9/16 allen head socket and a big breaker bar and a pipe wrench on the end of the plug and two of us wrenching .one of them cracked free right away the other was a quite a bit tighter . but in the end they both came out . also took each manifold bolt out one at a time and cleaned them up and put some never-sieze on them . also put two new drain cocks in the block .
do they make drain cocks for the manifold?
pics attatched . the inside of the manifold is full of crap .
and a small pic from the net of the drain cocks.