340 oil pan recommendation-stroker

I don't think radiant heat is going to add a whole lot to the oil temp.
It is heating in a very concentrated area , which has a constantly flowing pool of oil passing over it.
You have air cooling when you are moving that will carry most of the heat away.
Unless you really have to have a new pan , I think you should be just fine.
Even sitting and idling for prolonged periods , the oil isn't sitting in one spot long enough to gather much heat from the proximity of the headers to the pan.

Edited to add.......are your headers coated ? If yes , then you have no problem what so ever.