Have you tried towing it to see if it starts? Don't have the specifics it's my understanding that version automatic could be towed started, if it's a manual it's a non-issue. Also when your cracking it, are you getting anything at the exhaust? If your not seeing any unburned fuel it could still be air in the lines. Had similar problem with my 76 300D and my issue was timing

Good Luck,

Sal
76 300D
85 300D