In general I hear that headers increase gas mileage, but in other posts I hear they make mpg worse.

I want more power, but I don't drive crazy and I try to get the best gas mileage as possible. Usually around 240-250 with my cutout open.

So I am wanting headers, but I want to know what to expect with MPG.

Thanks.

 

usually an increase of power in the car will give you better gas mileage, unless it's an increase that demands more fuel.

You'll probably gain slightly (1mpg or less) or stay the same.

 

My 350 gained a whole lot of power, but the gas mileage stayed the same, at about 12mpg.

 

They will add power and should help your milegae provided you do the chip work to dial them in. I am not sure about TPI cars but TBI cars can see an increase in VE by up to 10% with a set of headers. That requires chip work to dial everything back in. Without the chip work you will have a little more power but you will also likely have worse fuel economy. With chip work you can have both. This may be different for TPI cars though.

 

On my 88 I have headers, high flow 3" cat, Dynomax exhaust, K&N filters, air foil, 3:23 rear gear with the L98 engine. Just took a highway trip and got 24. 1 mpg average. Pretty satisfied with that if only the tank was bigger.