Will I see a noticable horsepower gain by installing headers in my 89' IROC. I have read that smog legal headers are fairly expensive and the installing them is very difficult, I don't want to go through all this for a 5 -10 HP gain. Here is the info on my car: 5.7 L98 engine rebuilt from jasper
700r4 rebuilt /2500 stall converter
holley stealth ram intake w/AFPR set to 47 PSI
hypertech thermomaster chip w/170* thermostat
K & N filters, gutted airbox, screens out MAF, tpis airfoil
new cat (I don't know the brand)
Flowmaster cat back w/cutout
MSD 6AL w/ MSD ignition wires
3.7 posi gears
275/40VR17 tires

 

you did all that work and DIDNT do headers yet?

 

No, the previous owner did everything except the MSD 6AL.

 

Yeah, your gunna feel more power, especialy if you have any work done cam or head wise. I would deffinatly spend the money to get them.

 

Yes you will feel some hp. Most of all you have all this air flowing in and your not letting it breath on the exhaust side. You should notice a difference after everything else you've done. You can also get the headers without the smog parts depending where your at. There are not that much fun to install but, I think they are worth it. You should at least be happy how it sounds when your done.

 

Caution: You'll need the O2 sensor fitting, at least.

 

most headers do come with it a 02 bung, but the 68470's dont in the header... but the y pipe does.