I also had a smoking problem mostly at idle I picked up a upper rebuild kit with head gaskets and valve guides around $45 from rock auto.com... But the valve guides are only rubber "O" Rings. If I was to redo again I would have matched the size and picked up 6 "O" Rings for a couple bucks.
Also has anyone attempted using newer style valve guides caps from a 350 or 454 heads ????? my smoking problem did stop for a few months but is slowing coming back
Hope this helps you