I have used a long pry bar between the front crossmember and the oil pan rail. There is enough "give" to then insert a 1/4" or 3/8" drive 1/2" socket on a long extension. This works better with two people: one holding the pry bar applying pressure and the other using the ratchet extension and socket. The pry bar works best if there are Float-O-Motor rear mounts.
Be sure to turn the steering wheel all the way to the right or left (I can't remember which!) so that the tie rod no longer blocks access to the front four bolts. You'll see which way works better once you try this. For some reason, I can never remember which way gives more clearance.
It's a 50-50 chance, but I usually guess wrong 80% of the time on the first attempt.
Marshall