Woodruff Keys

- The 400's crank uses a unique woodruff key from all other SBCs. This is the metal key that keeps the harmonic balancer from spinning on the end of the crank. It is slightly larger than the standard 350 key. After some searching around, I found that I had to go to the local GM dealer. The GM part number is #8E73 106751 and the cost is $1.00.

- The funny thing about this part is that the dealer has to order 80 keys at a time. There was only one dealer in town who had the part in stock and that's in a city of close to 1 million people. When the partsmen looked up the history, he found that he had sold 15 keys over the past 10 years since he last ordered them. I bought an extra one just in case I misplaced one.

- You can purchase offset woodruff keys if you want to advance or retard your camshaft timing in relation to the crankshaft. Advancing the camshaft timing increases low end torque, retarding the camshaft timing increases high rpm horsepower. It is a way of moving your power curve up and down by about 200 to 400 rpm. This is based on moving the timing by 4 to 8 degrees.

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Copyright May 2011 Eugene Blanchard