My porting was too aggressive!
Thanks for the thoughts. It is not my daily driver, so bus will not be in my future.
It is not numbers matching.
I was thinking too that at best it would be a bandaid ( in the event other ports are similar).
I may fix it and drive it till it worsens, or until I can get a different set of heads.
It won't get driven much more with winter coming in a couple of months.
Good news is when I pulled my chipped up semi fenderwell headers off, the better half suggested they should be ceramic coated and look like chrome.. Nice when she suggests it LOL