I have a very original '77 911 NA Carrera with the 3.0 (European only in 76 & 77 I believe). The engine has just short of 80k miles on it. I've been told that I should look into a tensioner update kits that converts the mechanical valve tensioners to oil driven hydraulic tensioners. It seams to me that the hydraulic tensioners would have about the same risk of failure as the original mechanical ones. I'd appreciate any comments regarding this update. Is it worth cost, time and effort for the update kit, or is it better to just replace the mechanical tensioners at regular intervals.