Heatproof: Epoxy vs Polyester

[sildene]

I am fibreglassing a pipe (carrying wet exhaust from a diesel inboard engine) through a bulkhead, and am aware that epoxy resin has limited heat resistance. I'd like to cater as best I can for an engine overheating event.

However, despite a google search, and a forum search, I have not found good information.

Clues I have found so far:
1) Epoxy stick products (mixed by hand) I've seen state the maximum working temperature to be 250F / 120C.
2) Polyester filler/adhesive by a reputable manufacturer give a maximum working temperature of 374F / 190C.

The above polyester looks rather better than the epoxy.

Rather than a recommendation for a brand-X product, I wondered what the maximum heat resistance of common, garden varienty polyester and epoxy resins may be.
Can one extrapolate the above maximum working temperatures to all garden variety polyesters and epoxies, or are things not that simple? Any insights appreciated.

Martin