Sorry for the lame question, can i sling a trolley jack under the car at the front, on say, the engine block (or sump), or is this a bad idea?

Alternative positions gratefully accepted!

(Rear is OK, used the rear diff!)

 

I'm not sure what MY your talking, but on the classic I find that if you look just behind the wheel and towards the car slightly there is a massive structural bolt pointing downwards, I always centre the jack round that.