Congradulations on your purchase of the boat building tools and equipment.

That said, I can't tell you much about your old head other han it was most
likely built/designed before the requirement for holding tanks (or sewage
treatment). This head will most likely use more flushing water and fill
your holding tank much faster than the modern marine head.

I'm using an old (pre-holding tank) Groco, all bronze model myself and have
noted that it uses about a half gallon of flushing water on each flush. Not
good with a small holding tank. If I try to restrict the flush volume too
much, it becomes difficult to pump on the flush portion of the pump stroke.

My opinion and experience, FWIW.

Steve
s/v Good Intentions