the color of the grommet is really irrellevent. There really were only two types and they are interchangable. One has an extra plug on it for altitude compesation but it can still be used on any duraspark system , u just leave the extra connector unplugged. Ford used the same duraspark box on all engines. The v8, and straight six used the same box. The difference is the distributor. So the answer to your question is that box could have been used in any ford duraspark engine.