I had all sorts of starter troubles in a VK I had for a number of years.
Had a nice set of extractors.
Trouble is they were rather close to the starter.
I was replacing or rebuilding the starter regularly.
It was mainly the solenoid that was the trouble.
There wasnt enough space between the starter and the extractors for a heat shield.
The heat soak was doing funny things with the armature.
Eventually I found a bloke who had a modified starter motor.
It had been rebuilt with Ford armature, and main body with the field coils as well.
Pretty sure it even had the Ford solenoid.
But it is a long time ago.
After fitting it, I never had another issue with the starter motor.
Had the car for about 3 years after that.
Apparently the Ford stuff is better at withstanding the heat around the extractors.
The fella I bought it off was doing a fair bit of racing at the time, and he said it was a very common modification amongst those running 308s.
He had a VK sports sedan at the time and even ended up sharing a drive in the V8 utes a while back.
Asked him about the mods recently and he cant remember any of the details though.
Heat is a big killer of electrical stuff.
Ceramic coating the extractors is likely to make a huge difference, but would still consider heat shielding as a priority.
Heat shields too close to the starter wont work very well.
Need a decent air gap between the shield and the starter for them to be effective.