I have a set of early March manifolds that supposedly came off a Z28 the first week the owner had the car. The driver's side has the hockey stick style and they look original/untouched. That might push the date for the cars into late March or early April.

The '67 and '68 Zs used a smog tube and check valve for K19 equipped cars that stood further away from the valve cover than the more pedestrian 327 and 350 cars (different part number). This was to allow easier removal of the valve covers to adjust valve lash. I have forgotten if the '69 Zs had their own unique smog tubes for the middle position design that gave more clearance but I would guess somebody here knows for sure.

Engine bay photo of 1 owner 21k mile Z/28 built on or about September 29, 1969.

Even used on L48 engines. Vintage pic.

Thanks for all the help on this I'm putting the hockey stick on my car I'm looking for a hose

clamp smog dated 3/ 68 I just need one I have the other three