In addition to the late production '69 Z28, I also have a late production '69 Corvette (with the 350hp/350 ci engine. This car is a 41,000 mile orignal car which I've owned for over 20 yrs, having bought it from the original ower (a lady I worked with at the time). I had occasion to remove the valvecovers last night, and found that this car also had the 'dripper valve covers' This car was produced in August of '69, with the engine being assembled on 072569, very similar time-wise to the production of my '69 Z28 (owned for 33 yrs and which was also owned by a lady driver previously). With both of these cars having 'dripper' type valve covers, I'm thinking either 1) GM began putting on the dripper valve covers prior to the end of production in late '69, OR 2) these lady drivers couldn't stand having 'dripper less' valve covers on their engines, knowing that the '70 models had 'drippers', so they both purchased replacement valve covers?? (Both of these cars were in extremely original condition even when I purchased them in the 70's and 80's respectively.. I just wish there was some way we could pin down in a documented fashion, exactly when GM began using the dripper VC's..)