hole in my head
The 302 heads in stock form dont have enough port for a 340.imo
On the thought of repair, a pin job can be done as well as the plug screws, I have run them hard with no issue.
I would make sure to have at least high nines in the compression depot if running aluminum heads.
And 915 heads are a casting that was used on 340/360's, they work good, even better when ported.