How to get my car into 12 seconds?

Alright guys and gals, just looking for some input/ opinions right now on what you think it'll take to get my car into 12 seconds on the 1/4 mile. Now i'll start off by saying this, i'm 17 and work a part time job and am still in highschool full time so the budget is very very limited. So unfortunatly at this point bore/ stroking is out of the question, i just don't have the $$. My car is a 74 scamp and i'm in the middle of doing the /6 to 360 swap, i can't tell you for sure what year the 360 is, i can't read any of the ID on the sides of the block but i'd be really suprised if it was making much more then 8-5 comp. I know it's from the 70's, i'm guessing later on. Transmission type hasn't been decided yet, i have both a 904 and 727 that are being looked at by a friend of mine and we're going to use the one that looks better mechanically. 8 3/4 rear with a ratio like 3.55 3.91 max (this car will live most of it's life on the street with a little track time so needs to be street friendly as well). So basically what do i need to do to get it into the 12 second area? I know it could really use a set of heads but aftermarkets are not in the budget and by the time i get a set of j's ported and polished and valve job i'm not too far behind the aftermakets so...... Basicaly right now i'd like to know what i can do with what i have and some fairly minor mods.( cam, headers etc. etc.) Also i have no idea where to go in respect to a converer, any ideas??? Who is a good company to look at for converters?? Thanks in advance guys i really appretiate your input!!!!