First off, your #'s are too high. But that doesn't mean you can't be a solid 13 sec car, like others have stated. Gears, midpipe and some sticky tires will help a lot and should get u there if you're a good driver.
Gears: Get 3:73's. 4:10's are a lot for a 5.0 and will murder you on the highway. Also if you are going power adder 4:10 are a double no no.
Secondly, if you wanna take down 03 cobras, your looking in a different ballpark. 03's with a good driver should be a mid 12 sec car...and we all know how crazy they are modded. It's definatly a better idea to look at a 347 stroker rather then slap a blower on it. For now build up parts around the engine accordingly such as full exhaust, TB, MAF, Fuel...etc and so when you do get the engine, you can benefit from the cubes.