CALLING ENGINE GUYS/GALS

It looks to me like neither the valves, or the seats were ground, you can still see pits in them. Looks like they just lapped them. Your leaking valve job isn't going to magically fix itself. The bores look terrible, and it is quite comical to expect a engine with that much leak down to seal up once the rings "seat" PLUS it's a numbers matching 340 we are talking about, not some 2 barrel 318 in your old farm truck.