Most likely a 6.247 as 6.354 was a bit heavy for landrover.
Perkins engine models of this era were coded number of cylinders followed by capacity in cubic inches so 6.354 is 5.8 litres 6.247 is 4.050 litres.
The 247 engine was found in the old dodge 50 series light truck/van and also in mazda pick up for some none uk markets
It wasn't a bad unit in the dodge 50 and quite smooth and hi revving for a perkins
This should help you identify it
https://www.powerlinecomponents.com/literature/perkins/per_number_guide.htm