it would go through the hood no problem, I reckon you'd need quite a large quantity to go through the engine block though ...
I remember this being done in school, in a fume cupboard. A test tube was filled with the mixture, a magnesium ribbon inserted as a fuse and whoosh! Quite exciting, but it didn't burn the school down
If I can still remember any chemistry, it'd be an exchange reaction - the iron has the oxygen but aluminium is much more reactive so it grabs it. You don't get to use the test tube for anything else afterwards by the way.
Fe2O3 + Al -> Al203 + Fe, that is
iron oxide + aluminium -> aluminium oxide + iron
so you've basically got molten iron dribbling around - don't get it on your fingers eh?
buying ingredients would almost certainly be a lot easier and better than making them. It shouldn't be too dangerous, but the three golden rules are:
1) use a small quantity to start with
2) use a long fuse
3) wear goggles, at least until you know what kind of fireworks are likely to happen
good luck anyway