Porting small block 915 j-heads

I’ve ground thru the short turn on two SBM heads.

One was a J head that was already ported, that I was trying to tweak for the customer.
It was a small hole and I repaired it.

I had based what I was trying to do with it on what I had found working well on a core head I was messing with.
I had really laid back the SSR on that one and it was working quite well.
I never even got close to having the SSR on the J head laid back that much before I saw I had “dimpled” it.

So I took that core head and tried duplicating the short turn on the neighboring intake port.
It never even got close before a hole appeared.
The “good” port was just abnormally thick in that area, so it didn’t break thru.