Question about heat and cam bearings

[raveer2000]

I just picked up the block (SBC) from the machine shop and had it bored, line honed, 0 decked, and had new cam bearings installed.
The owner has this idea of powdercoating the block. The machinist says the 400 degree heat could melt the new cam bearings. Anyone have any experience with this. Will 400 degrees for 20 mins hurt the new bearings. I think the machinist was more concerned with powder getting on the freshly machined surfaces, which the powder coater has assured me it won't happen. Any suggestions would be a great help