The BEST option: Here is without a doubt THE BEST single bolt timing chain set on the market. Both the cam and crank gears are fully machined in the USA from solid blocks of billet steel. To make degreeing the cam easier, the 9 way adjustable crank gear has every position engraved with the advance or retard numbers for that specific position. The 9 different keyways allow for aligning of the camshaft at virtually any position needed. This set also includes a double roller chain that uses heavy duty independent seamless "TRUE" rollers. Detailed instructions for installation are included. The best single bolt set you can buy, at any price. The chain uses heavy duty independent seamless "TRUE" rollers. Actual shape/appearance may differ slightly from the picture.