How to get my car into 12 seconds?

Welll being in the same boat... broke and young haha I get what your saying. Going faster is pretty simple.. more power to the car or less car to the power... So cheapest way is drop everything you dont need or care about. Its cheaper to throw stuff off then add it on. Heater,ac,spare tire, all that kinda stuff if you dont mind, This would be the less car to the power.
Then the side of things is more power, If it were me I would toss a 440 in it.
It sounds like your just starting the build and this is the time to decide.
you can pick up a good 440 and trans fairly cheap and it would cost much less to get into the 12's. any mild cam,intake,carb 440 can get into 12's very cheap but thats just me. If you go the small block route I think it will take a little more motor, if I built a 360 non stroked I would go 10.5 compression,decent pistons,solid cam in the 550+ lift cam,roller rockers mite do it. Good luck to yah either way!!!