General Question:
I never had any smoke issues with my xj40. But a few days ago i raised the car on the front with the back wheels still on the ground. It stood like this for a few days. After putting it back down and running it, the tailpipes smokes quite considerably.
I was scared, but after 20 min of driving it went away and so far(100km more) it didnt come back.
Is there an explanation to this?
Oil pooling at the rear of valve cover and seeping past the valve stem seals into the cylinders.
okay, but is this normal on any xj40 if they are inclined heavily?
I tested compression 4 months ago and it was all fine and even
thanks for your time btw
I do not know about the inclination in particular, but it is very common (normal?) for XJ40s to blow a puff of oil smoke after sitting (even level) for any time, even overnight. This is because the engine is canted to the right so as to allow for a lower profile hood (bonnet). Engine oil on top of the head will pool to the right, submerging the exhaust valve stem seals. As those rubber seals age and wear a slight amount of oil seeps past them and is burned when the engine is fired.
okay cool that makes me feel a bit more relaxed 
cheers and thanks