One of the earliest available releases of BuildCraft, by SpaceToad.
I haven’t found the correct source files for this yet, but they should be somewhere in this subversion repository: https://sourceforge.net/projects/buildcraft/
This is for minecraft beta 1.4, NOT beta 1.4_01 — pipes don’t seem to work in 1.4_01.
You’ll need to install Risugami’s ModLoader from here: https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-mods/1272333-risugamis-mods-updated in order for this to work — using MultiMC will probably be the easiest way to install this version.
