I just bought a 1989 mustang GT 5 speed a couple days ago. I know they run 225hp stock and mine has a few mods so i was wondering what it'd be making now. It has advanced engine timing, underdrive pulleys, K&N intake, 1 3/4" headers, 2.5" exhaust, ported heads, and a Centerforce clutch. I'm thinking somewhere around 275hp but i'd like to hear from anyone whos a little more experienced with tuning them.

p.s. is a port polish the same thing as ported heads?

More like 250hp at the flywheel

To port and polish something is porting it, u can port heads, intake, throttle bodies,etc. Port heads are heads that have been ported and polished which is openeing them up more so they flow more air

I bought an 89 GT vert in 89 and it was advertised at 225 HP. Soon after they pulled the "225 horses are bound to kick something" ad. 225 was a false claim, I believe it was more like 205-210 in stock form. That is why my 05 V6 test drive felt like my old 89 GT with less torque. I can't wait to drive my 06 GT!

They did come with 225 from the factory, at the flywheel this equates to just under 200 rwhp through a 5 speed, a little less through an auto. A rough estimate is to take of 15% of flywheel horsepower for a manual, around 18% to 20% for an auto.

From you mods, I would guess you may put down around 215 to 225 rwhp.

The only somewhat major mod you have is ported heads, and they dont help crap when your running a stock intake and cam.

Take a section of 1" hose, and a section of 3" hose. Cut the 1" hose in half, and connect the 3" hose in the middle of your two halfs. Guess what, it still will not flow any more than the original section of 1" hose. In a sense this is what you have done with the intake/exhaust path in your engine.

They did come with 225 from the factory, at the flywheel this equates to just under 200 rwhp through a 5 speed, a little less through an auto. A rough estimate is to take of 15% of flywheel horsepower for a manual, around 18% to 20% for an auto.

From you mods, I would guess you may put down around 215 to 225 rwhp.

The only somewhat major mod you have is ported heads, and they dont help crap when your running a stock intake and cam.

Take a section of 1" hose, and a section of 3" hose. Cut the 1" hose in half, and connect the 3" hose in the middle of your two halfs. Guess what, it still will not flow any more than the original section of 1" hose. In a sense this is what you have done with the intake/exhaust path in your engine.

They did come with 225 from the factory, at the flywheel this equates to just under 200 rwhp through a 5 speed, a little less through an auto. A rough estimate is to take of 15% of flywheel horsepower for a manual, around 18% to 20% for an auto.

From you mods, I would guess you may put down around 215 to 225 rwhp.

The only somewhat major mod you have is ported heads, and they dont help crap when your running a stock intake and cam.

Take a section of 1" hose, and a section of 3" hose. Cut the 1" hose in half, and connect the 3" hose in the middle of your two halfs. Guess what, it still will not flow any more than the original section of 1" hose. In a sense this is what you have done with the intake/exhaust path in your engine.

It has intake on it

Is your intake manifold stock or aftermarket? In your original post, you said the car had a K&N intake which is a cold air kit only. Even if you have an aftermarket intake manifold I would still agree that you are making 250 hp at the flywheel and maybe 215 - 225 rwhp. Torque production is probably in the 260-280 ft/lbs range if the long block is in good condition (ring seal, valve seats, etc.).