This performance modification replaces the original steel drive belt pulley located on the front of the engine, with a smaller diameter and lighter aluminum pulley. This results in less parasitic loss from driving the accessories (power steering pump, a/c compressor and alternator) as they are turned slower and also from the lighter weight of the new pulley. This should result in more power and higher fuel consumption.
The original pulley is a mammoth and must weigh 10lbs. The new pulley is much, much lighter and about 1" smaller.
First you have to remove the belt covers. This is easily done by removing two screws and a nut on one side. With this done find a 22mm socket and a big pipe. Mine is 3' long. You have to stop the pulley rotating while you are cranking on it. I put the car in 5th as it is a manual and pulled the handbrake on. If you have an automatic you will have to rig something up to stop it turning. The bolt is hidden in the center of the pulley and will take a lot of effort to loosen. It unscrews anti-clockwise just like a normal bolt. With the bolt loosened a bit slacken the two belt tensioners using 12mm socket. You also have to loosen the locking nuts, one on the left tensioner and one in the center of the right tensioner wheel. Remove the belts, the pulley bolt and the pulley itself. It should come off easily.
My new pulley from JC Sports had no marking for TDC so I transferred the mark from the original pulley and put a knick in the inner flange with a file so it will always be visible.
After installing the new pulley I installed new belts as the old ones were., Well, old. And too short. I used a 33" belt on the left and a 34" belt on the right. The left belt was a bit tight but a 34" was too big.
Alternator output at idle with the lights on remained the same at 14 volts and there were no strange noises................................performance to be assessed.