2X8.... use em love em use em again and love em some more....
i drive around from full slam to 1" from full slam all the time, and I jack up the car often also...
First off DO NOT THROW OUT YOUR STOCK JACK...... it can get in places no other jack can... sure it's hard to use, but it has a very low profile... Second if you can't get any jack under, then drive the front wheels up onto the 2X8s... if you still cant then use a 4X8 just in front of that...
finally go to the store and buy another floor jack, but get one with a very low profile... anything under 5" and you have a score of a jack....