There is a screw-in plug in a recess in the same location where the block drain cock resides on the B18 (the rear passenger side). With the exhaust manifold, down pipe, and oil filter obstructing, it's a bugger to remove with the engine in place, but it can be done; although, removing the lower radiator hose is less of a chore. While I had the engine out I screwed in a drain cock from a B18.
Bob S.