I bought a FV motor and trying to figure out who the builder is. It has all the good stuff like 1600 dual oil case, full flow fittings, 373 heads with polished ports and lightened rockers, lightened flywheel etc. The only markings are on the front of the block and it has a stamp that says Z104k. The 4 is turned sideways. I have attached a photo. Anyone have any idea who the builder is? The normal vw engine codes are not there and it looks like they never were so it may be a new case.It also has a stamp that says 10 69. Maybe the engine was originally built October 1969?