I called Lockwood. The fuel block - manifold - restrictor - whatever you want to call it, is apparently, just as we've been talking about. Here are the essential items that my phone conversation touched on:
- orientation of the manifold block itself, is a non-issue
- [Lockwood reportedly prefers to] mount fuel pressure senders (and therefore the manifold) such that the pressure opening of the sender points straight down (to prevent fuel from pooling (sitting) in the sender (particularly during non-use I should imagine) and reportedly a best practice of fuel sender manufacturers (that's inverted from the picture posted at the beginning of this thread)
- no requirement for the fuel pressure sender to be mounted on the manifold block itself - that port may be plugged and the sender placed elsewhere
- ultimately - fuel sender (and block) orientation according to builder's preference and/or sender and/or kit manufacturer's guidance
- preferred location of the manifold block is after the gascolator and fuel pumps, but before the fine filter
- not having a [separate] coarse filter [at all], upstream from the manifold was mentioned as preferable
Disclaimer: Please do not take any of this information as authoritative or as any sort of recommendation.
Thats' what I've got so far.
Cheers.