output??

first if you have the stock crank in the engine, a .030" overbore will put the displacement at 292ci. if you are using the stock cam and heads, you should be making about 200hp at best with a stock engine.

if you add aftermarket heads like the world products windsor jr heads, you will pick up about 40hp out of the box. add a cam like the comp cams he268h high energy cam, and you should pick up another 20-25 hp. if you use an xe262h extreme energy cam, you should pick up 25-30 extra hp over stock. as long as the exhaust system is reasonably free of bends, and the headers are a decent header, you wont gain much power over what you have now by upgrading the system.

thus with the aftermarket items i suggested, you should be making around 260-275hp at the flywheel, which is pretty good for a mild 289.

run a 3.25-3.50 rear gear, and a T5 trans, and that stang will run fairly hard on the street, mid to high 14's roughly, and have very good drivability, and decent fuel economy if you keep your foot out of it. by the way, top the engine with a 600cfm edelbrock, holley, or demon carb. do not use a double pumper for the street as your fuel economy will go in the tank.