Can anyone please confirm will the seats from a 1979 xjs fit in a 1989 xjs ? Ive been offered a 1979 xjs with great interior and the drivers seat in my 1989 is bit shabby so could i swap all seats over ?

 

They will not without modifications and welding to the floorpan fixings. The earlier seats are about 1 inch wider between the runners where the runners fit to the floor seat towers. The later seats came in about 1987/88 or so.
Greg

 

Good to know, Greg. I didn't know that. I would think that since the earlier seats were wider that you could take the gear from your newer seats and fit them to the older ones. It's entering into the realm of custom fabrication work, though, so there won't be a whole lot to go on. I'm not familiar with how the mounting plates are attached to the seats, but it's possible that you could just make a couple brackets and have that be it.

Keep us updated, this would be good information to have documented! Best of luck.

 

so the fronts will need messing with but how about the backs are they the same ?

 

It is not the seats or the runners that are the problem, but the floorpan towers they fix to. The towers on your floor will be too close together for the older seats to bolt to. Changing the runners will not help solve that difficulty.
The outer floorpan towers (the two nearest the door side of the floor, front and back) will have to be cut, and welded in a changed position to accept the older seats. The runners just bolt to the towers. It is quite important to weld properly, rather than use (for instance) an adjusting bracket and a couple of bolts, as seat fixings are safety critical in a shunt.
In the pic below, you can see all four fixing points, and it is the bottom two in the photo that you need to refix further outboard to get the older seats to fit. The fore and aft dimensions are the same, and the back seats and door cards, rear armrests, tunnel console are the same, except that the rear seat cushion may not have a central cutout for the rear seatbelt buckle, if rear belts are fitted to your car.
Greg