epoxy for ports

[chris mc bride]

Might be kind of off beat question. Ive seen few articles on heads where they had a epoxy to build up inside of ports to acheive differant shape to port for flow gains. Wondering if anyone knows which epoxy is used and maybe a company that sells it. Im working on some heads for race project and would like to test few ideas, Ive already did some flow work on these and results look good but real proof is on the track. These are billet heads and welding will be final part if all works out. Problem would be welding is more permanent thing and not as easily changed.
Please I know risk of epoxy in ports but this is just a alcohol injected motor no blower so Im wiling to take risk.