By checking the cam timing position of BOTH the intake valve and the exhaust valve, engine builders are able to determine the accuracy of BOTH lobes on their cams, and if necessary or desired, make adjustments to compensate for variations from specifications (and to dial in the cam to best straddle the differences between intake and exhaust readings). STOMSKI RACING’s SR098E- 911 EXHAUST Cam Timing Fixture, allows these engine builders the luxury of an accurate and easy fixture to repeatedly and precisely mount a dial indictor over the exhaust valve. Our SR098E is designed for use with an AGD style 1” travel/dial indicators and includes hardware for mounting on 911 engines up to and including the 993. One fixture is reversible and fits either #1 or #4.