Did it on my Williams recently,
Changed the abs brake servo(2ports) for a non abs(4 ports)
(kept the master cylinder)
Completely changed the front brake lines,
Changed the two rear brake lines in the engine bay only(they unscrew under the bulkhead...passenger side)
I also removed the abs pump and wiring.
Good When my brake servo starts to leak...I plan to upgrade to the cup one as its suppose to be bigger then the Williams!