Trying to get our servers modpack on to curse forge and we hit a snag, Buildcraft pre-release for 1.8.9 is not on the third party list and can not be added as buildcraft is on curseforge, they will not add build craft pre to the curseforge entry as it cannot yet import a 1.7.10 world to 1.8.9 (totally understandable) however they are happy to have the mod in curseforge mod packs, see this blog: http://mod-buildcraft.com/state-of-1710-and-189.html
they specificly reference it, i was going to quote that part, but its half the blog post so does not need to be quoted.
Now as i understand it the thirdparty list is there to prevent us modpack developers from sharing mods that the author does not want shared (again i fully understand and agree with that, it is at the end of the day the mod authors work and down to them how its distributed) however in this case curse forge is kind of going against the mod authors wishes by blocking it from custom packs. its a special case that really needs looking into.
At the minute the only "viable" solution is to export it with out buildcraft and put in the description "users are urged to download the required build of buildcraft from *LINK*" and when mods require buildcraft that will cause many issus being reported (we all know users dont always read descriptions fully....and we have all been guilty of that ourselfs