Re: zh queries
I take you mean yo have a P6 LTD. That is, an LTD made from 1976 through to 1979 with the Rolls Royce grill.
The engine number is on the front left hand side of the block on the vertical side of the timing cover casting. If yo have the AC brackets/compressor still attached, it may be a bit difficult to see. It should be JG71... both on engine and chassis. These numbers should also match the number on the left hand shock tower
Yes, all P6 LTD's had the 5.8 fitted as standard. On the plenum chamber wall you will see two small aluminium plates. On these plats will be the chassis number, vehicle type etc. It will also show engine type being a 'T' which is a 5.8 4V engine witha transmission type being a 'B'. The B denotes floor shift automatic.
With respect to engine bay similarities, all XA - XC and corresponding Fairlanes/LTD's are pretty much the same with extractors in mind.