Don't know what to do now there's a lot less work in the complete engine and it's got some history the other one is an unknown and just someone's word ?!?!?
Is there any non root's engine upgrades that have been done in the past for more performance using the std gearbox sd I don't want to loose my 6 speed ???
The second engine will need the same things swapped over (water pump, sump etc) and your six speeder will fit straight on, a lot less work than modifying a none Rootes engine to fit - and you could always sell the OD box on to get some cash back