The resins you seek are not easily handled and are rather expensive. Require specialized storage as well. Suggest you talk to Henkel (Loctite Hysol) and discuss their aeros resins. Also Master Bond, info on web. Your intentions very expensive but if thats what you wan to do... Remember that some Hi-Temp composite assies require autoclave curing. Current carbon/expoxy composites for aerospace can meet 230F at most design SERVICE and can take spikes to about 425F.
Since you might need some "fudge factor" I would look into Polyimides. (Even older PMR-15, widely used, seems to meet your goal and used in engine nozzles, nacelles etc.)
If you are an experimenter, talk to the people at Langley (Hampton, VA) also, but I think the people at Henkle (US offices) will give you correct information. Thats a start.
Regarding PMRs: they contain MDA - methylene dianiline, which is some serious health risk and they are being modified due to it. (Just google it and see what planes and workers made with it got in bad shape over it, so be careful. They may not even be available to you.) Visit www.ube.com. go Aerospace materials: PETI
Anyway, good luck and all appreciate new stuff being tried. Worked the stuff some apps, but materials really in infancy. Hope it helps since without specs difficult. Heat transfer via some kind of thermal blanket? I worked design APU plenum and the current maker informs me that the current cost of the resin material is $900+/pint. Just to give you idea of costs. (Did you consider ceramics ?)