Not sure the drive, except in all-out race engines, is worth the $ or effort. Jay's easy-to-change cam gear set-up and removable upper timing cover seems a much better idea for a few reasons. All chains stretch a tad after a few miles or hours. By making it easy to check but also advance the cam gear a tad afterwards, one can regain the exact timing one originally set the engine for. 'Course playing around with advance/retard cam positions after the chain has stretched is another great advantage to optimize engine/cam performance.
The belts I understand do stretch too but I had heard they don't stop stretching. After some usage, the fear that the cogs may start shredding (hey, face it, they ARE used in mighty high hp, high stress engines) forces a change to a new belt. That's methinks the reason NASCAR shops, which sell btw just about any part used, does not sell used timing belts as they are thrown away by the bucket load. Chains on the other hand, even in high hp engines, can be expected to last a very long time at zero$.
Just wish a cam gear and cover setup was readily available for my SBF's! Oh, well!
