I dont recall if my TJ had a hood-prop (the metal rod that you pivot up to prop the hood open).
I do recall several times just carefully laying the hood back against the windshield (as mentioned above). No harm done, so long as you are gentle and dont let it slip outta your hand. Placing some sort of padding between them certainly cant hurt.
While you are tinkering around under the hood:
The box that has the airfilter in it (we call it an airbox) has a funky trumpet look'n thingy on it. We call that a "trumpet" cuz we likes to get all creative and sh_t.
It has that shape to facilitate cooling the intake air and thats why you dont gain much by adding an after-market cold-air-intake gadget.
Anyhow...my personal recommendation is to rotate the inlet of the trumpet downward to an angle...I think I had mine at like 7-O'Clock or something like that. My reasoning: Just in case a decent sized puddle were to sneak up and fing itself under me while I was innocently motoring along (cuz I would never intentionally play in puddles
)...and just in case a BUNCH of H2O accidentally got itself splashed up inside my engine compartment. The trumpet angled downward would be LESS likely to funel water into the airbox.
A little water aint gonna hurt you. A lot of water will. Im not exactly sure where the fine line in that destinguishes enough and too much.
Thats just MY perference. Others with more experience will likely have better advice.