Gear drive!

Gear drives are expensive to purchase, and they are rarely drop in, usually requiring some work.

Another downside is that they are more prone to transfer vibrations between the crank and cam, where as a chain will more readily absorb the vibrations.

Personally I wouldn't run one unless you needed the extra strength. A friend has one in his twin turbo belvedere, and it sounds ruthless. Not to mention it confuses people because they think it's supercharged, until he step on the throttle and the turbos spool up .:thumbup: