When the LT-1 engines and other EFI engine makes were introduced into drag racing, Jim Skelly was the guy that approved the use of aftermarket EFI ECU's and also approved the use of the crank trigger systems on engines that have a crankshaft position sensor in lieu of a single distributor that handles the ignition duties. The current language that everyone has used throughout the years was written by Jim and has not changed.
This same issue has taken place with other engine makes of ignition systems that have been previously approved by NHRA and later on deemed to be illegal only to be rescinded when NHRA found the original acceptance.
Below is a depiction of the OEM crankshaft sensor position on the LT-1 engine and Jim did not see an issue allowing the use of a crank trigger system in lieu of the OEM sensor because they both perform the same function.
