For Use When Servicing the Timing Chain on GM 2.8, 2.9, 3.0, 3.5, 3.6, 3.7, and 4.2L Engines. Helps Ensure Camshaft Alignment During Timing Chain Removal and Installation. Plates 1, 2 and 3 work on 2.8L, 3.0L and 3.6L high feature V6 engines. Plate 4 works on �04-�07 2.8L, �07-�12 2.9L, �04-�06 3.5L, �07-�12 3.7L & �02-�08 4.2L in-line 4, 5 and 6 cylinder engines.