New Competition Cams pushrod length checker. 6.800 to 7.800" adjustment range (7.400 is LS1 stock length). Pushrod length tools are excellent and inexpensive, and allow you to find out the proper length pushrod require when installing aftermarket cams, different thickness head gaskets, or your cylinder heads have been machined. Stock LS motors us a non-adjustable valvetrain, so proper pushrod length is crutial to those engines.