Dont need BOP plate, just get a BOP housing TH400. 100$ @ junkyard + $xxx for rebuild...depends on who you know and how much you get done to it. Bare minimum is clutch/steels, sprague, drum mods, tranny brake

... again, depends...
Yoke... goto junkyard/D.S. shop... the truck one is much larger/longer - you dont want/need that one... You will also need the proper tail housing for whatever you choose to use on the DS end - the short tailhousing is what you need. Be real careful with the yokes and ends for the 400's... there's some wacky stuff out there I found.
Driveshaft... $300-400 for 3.5" Aluminum or high-grade steel (nice DS probably needed if you're doing all the hassle to put a 400 in there anyways). $100 for stock one cut/rebalance...although a stock DS will break with an even mild 11/10s car - if you wanna transbrake it, forget the stock DS.
Tranny mount... use same one as 2004r just oblong holes and weld support in the ends as "ears" (optional).
Dipstick... $10 junkyard or get a nice $60 Lokar that doesn't leak... (my stock tube leaked so I got a nice double oringed Lokar knockoff).
Phil