The pumps that we use have a high grade fouroelostomer seal on them, they are uneffected by drying up, or exposure to any modern fuels, including E-85.
Same deal with the needle/seat assemblies.
The gaskets are the higher quality "non-stick" and "non-shrink" variety.
Don't be fooled by any "blue" seals you might find in any over the counter kit. They are NOT the same as the ones we use, and they will swell up when exposed to ethanol or alcohol......Cliff