Holden 308 red starter alignment

Just replaced the starter motor on my red 308 with a later model unit from the 304 (Bosch unit). I swapped them over myself.
While it cranks over really well and starts easily, it has a intermittant clashing sound while cranking. Sound lasts about 1/4 of a second and happens usually once during the start.
Reading up online, they can be out of alignment and you can shim the starter motor to realign it.
Has anyone else had to do this? The last unit wasn't shimmed and I wanted to check before returning to the auto elec.

308 you dont need to shim, what you will more than likely find is that the ring gear is slightly worn in a couple of spots. generally the areas that are away from the 3 torque convertor bolts as the flex plate will flex more in those area's. jump underneath and turn it over by hand and inspect the ring gear