want to take out engine and box, any pointers on removing reaction plate with 4 bolts without stripping threads, reggie...........

 

The jaguar manual covers this-I can cut and paste or scan info for you if you don't have

 

The high torque pressure from the torsion bars is held by the Reaction plate, so it is very hard to take out the two bolts on each side that go through the plate.
Jack up the front, so the wheels hang down.
The manuals tell you to remove one of the bolts and then drive a 3/8" rod about 8" long in its place. Now remove the other bolt and drive a rod in it's place.
Repete this process on the other side, now take out the two big 1/2" bolts that go through the frame rail and the reaction plate. Drive out these bolts and replace them with grade 8 new ones. Now if you are going to rebuild the front suspension, remove the lower wishbone mounts and drop the spindles free.
This will make those 3/8" rods you put in the reaction plate easy to tap out. BUT,
If you are not doing any suspension work then carefully tap the top 3/8" rod so it just clears the torque reaction plate, leave enough of it in the bracket to hold things in place. Now tap the lower one out, each side and remove the plate with lots of prying.