Does anyone know if the xjs v12 front subframe will bolt on to a series 1 xj6? The xjs is is a 86 the series 1 is a 72. I am doing this as the brake parts are a little better performing and still available and cheaper as rebuilt, plus it has a larger sway bar. I think I will have to change the springs as the 12 uses higher springs to offset for the bigger engine.

Thanks

 

Yes the sub-frames are dimensionally the same. The are a few key differences between the XJS and XJ6. I think your early XJ6 has the tall rack and the XJS has the short tower rack so you will need intermediate shaft from a Xj12. I don't know if the XJS intermediate shaft is the same but it might be close enough.

I think you should do the swap... list of benefits as I seem it are below. If your rack is ok and you like the slower steering You can also simply swap the spindles and control arms.

Bigger vented front brakes.
Larger wheel bearings and improved seal design.
XJS rack steers quicker (better ratio) than the series 1 & 2 racks.
Larger front sway bar.
Better parts availability. (tie rods, calipers, wheel bearings, seals, pads)
Opportunity to replace steering intermediate shaft and check steering column. If there is play and / or friction in the intermediate shaft joints, it will greatly effect steering feel.