If both boxes are for Series XJs then, yes, they can be bolted on. But five speed manuals are quite rare, is your friend sure it's for the XK engine rather than an AJ6?
I got my manual gear box for £300 about 17 years ago, don't know if they've changed much in value since. Had to source a pedal box, flywheel, clutch, release arm and bearing &c separately. The centre console is different, as well and routing the electrics for the overdrive (if your box has one) requires a bit of modification.
I got my manual gear box for £300 about 17 years ago, don't know if they've changed much in value since. Had to source a pedal box, flywheel, clutch, release arm and bearing &c separately. The centre console is different, as well and routing the electrics for the overdrive (if your box has one) requires a bit of modification.