Is there room to pull a 318 out of an 80 dodge with the hood on and not damaging anything. I just painted it and would like to leave the hood on when I change the motor.

yes not a problem if it is engine only, you will need to roll the truck out of under or roll the engine hoist up and out. i personnally like rolling the truck so the engine does'nt swing around

I pull the hood whenever I do an engine just so I'm not putting my back against it while working on things at the back of the block/ and the amount of extra light let in without one in my way is worth the 4 bolts that everyone seems afraid of taking out when doing an engine swap....whether truck or a body....
Have I done it without pulling the hood? Yeah. But taking out those 4 bolts just makes it soooo much easier.

If you pull the hood be sure to outline the hinge mountings with a marker so you can just put it back where it was.

I drill a hole in each hinge the hood and use a pin to relocate it when reinstalling the hood.

I have pulled the engine from my 88 with the lift plate bolted to the carb pad, one set up was a ld340 (pretty high), just needed someone to lift the hood a little extra for the last little bit.

i have done both of these over the years on all kinds of vehicles, as well as using a scribe to outline the hinge position if one doesn't care about the paint, or will be touching up the paint in that area when the engine transplant is done.

Usually it isn't necessary to mark anything, as paint fade or a repaint creates it's own line over the years.