Have ran and seen them run like this for 4-5 years. Never seen one w/ added bearing on crankshaft. A horizontal block would bolt up to frame or plate easier. Not sure if this block has oil filter, one that does has a boss to tap into oil from pump that can can be piped anywhere (one w/out might). If turning high rpms (with a good balance) 8k+ tap oil to flywheel side crank journal and drill typical provision to rod journal for added lube and cooling to rod. Also might have to tap to valve cover to spray on valve train as "some" in this orientation have had excessive wear in this area. Rate of excel is considerably faster on "most" in a horizontal setup. Your build looks great, might consider slight taper to cylinder and plateu hone w/ light tension rings, check out specs on an animal (can open up considerable top end rpm's).