Big block, manual, with air
I have had several 3rd gens, 5 to date, and I've had a big block, with auto, and air, in a 74 H/B, it can be done, but you have to use very specific parts to keep the A/C box out of harms way. Start with a 73-74 Ventura/Omega/Apollo, A/C box and internals (evaporator, expansion valve, hoses), they angle more toward the passenger side of the engine compartment due to the wider Buick/Olds/Pontiac engines. In 73 and 74 Novas switched to the subframe mounted later style "caged" mounts with clamshells on the block, so it's no problem getting it in there, and you have fewer issues with the height of the engine, headers are lots of fun though, I'd consider doing a bolt in rack and pinion conversion, just to free up the space for headers. If you are dead set on a stick, I would seriously consider a T56, 6-speed, just for the ease of use, availability, and strength. The T-56 uses a hydraulic clutch, much more "user friendly" in traffic (ask me how I know), or if an auto is an option, I'd consider an Art Carr 2004R, either way you get the benefits of an overdrive to keep your final drive ratio sane. If I can help you to locate any of these parts, holler at me, I live across the street from a "classic car" wrecking yard, he has 30 X-body's to choose from including at least 4, 3rd gen Ventura/Omega/Apollos.
Good to see some girls, or young ladies, getting interested in this hobby:yes:.
Hope this helps, Pat