New Mustang owner

[mikeb89GT]

Hey everyone. Been reading the board for a while now, and I have finally got my 89 GT. I have been wanting a mustang for a very long time. Now here is my first question. The guy that sold it to me said he was getting mid 13's on the track. From what I have been reading this seems unlikely to me. Seems like alot of people on this board with alot more mods than I have.
302 @ 306ci
full exhaust
shorty heads
pro 5 shifter
3.73 gears
K & N filters
mass air (could someone explain this to me)
and I think he said polished heads. As u may be able to tell I am just getting into this kinda of stuff (currently a computer geek ) Anyways what do u think about this setup. I may be missing things. Do u think that 13's are possible with this car?

Alos is there a way to tell if the stock cams are in it or aftermarket ones were added, he didnt know because he acquired the car from a relative.

Also what do u think I should do next, I would love to run it this spring.

Mike