In lieu of the customary valve assembly-holding setscrew, a ram, slidably engaged with the central bore of a valve housing cover, is adjustably held against the valve assembly by a plate-type ram cover. The latter cover is bolted to the valve housing cover. To insure that product gas can not escape from the valve housing, the ram has an annular shoulder thereon which prevents its removal outwardly from the housing cover; the ram can only be removed via the inner surface of the housing cover. Too, the ram has an O-ring seal thereon which is confined between the ram and the housing cover.