No modifications needed to install on 5.5 & 6.5hp clone engines
Expect quicker acceleration using this flywheel. Check with your rules before installing.
NEW For 2018
Arc has revised their 6619 flywheel. It now has shorter cooling fins for less air drag.. The new number is #6689 and Named Speedway Edition..With a stock key the ignition timing should be in the 32 degree range
