I've rebalanced probably 12-15 flywheels for theLT guys---the Camaro/Firebird guys are switching between at and 6m and theres always a overlooked flywheel balance---those engines internal front/ex rear---gm didn't have to cut a keyway for dampner as spark being controlled by ecm---mech don t need timing marks---so GM engineers being the departmentalized group they are--the crankshaft guys internal the front but leave the rear external since one piece seal came out---

REmember when 396 came out???The intake manifold guys out ranked heads guys so head guys had to build intake ports to fit manifold-----