I am fixing up an 89 f150 xlt with a 5.8L i just ordered bbk shorty headers. I am planning on splitting the exhaust out of a magnaflow muffler out the back. I am eliminating the CAT and o2 sensors. Is a 3" exhaust pipe from the headers back too much. will it cause a back pressure issue if i go that big? any feedback will be much appreciated.

 

I would go 2.5" max. You could potentially lose torque going that big. 2.5" duals are good for up to almost 400hp I think.

 

Can't eliminate O2 sensor.

If you do, then just remove the bulb in the dash for the Check Engine Light so it doesn't remind you its needed. Expect a catastrophic hit to fuel mileage.

 

Leave the o2 sensor alone. If you remove it, your mileage and power will plummet. Also you will most likely have driveability issues.

 

Thanks I'll leave the o2 sensor in. I am not going to run duals I was just going to run one single 3" will that be OK

 

I think that would be fine

 

I used a Bassani y-pipe and Magnaflow 3" converter, pipe and muffler on my old '92 F350 w/5.8L engine. The truck ran fine with no seat-o-the-pants loss in low end torque. Ditching the factory monster converter then using a hi-flow replacement was well worth most of my gains.

 

I've been considering something similar. Question on the O2 sensor: how important is the location, and is there a major effect if you run it on just one bank? I realize as you move back the system temp may change, but I would think the O2 levels would be the same. Could one run duel exhaust and simply change the location of the O2 sensor to just read one bank?

 

Thanks for the advice! I will definitely keep the sensor in and im going to run the 3". frantz im not sure about that. as long as you dont go to far back you should be ok. I am going to have a custom Y pipe made by a friend. ill let you know how it all works out.

 

It is quite common to have the O2 sensor setup to sample only one bank when using a custom exhaust.

When you have OBD-II that is a different story. Both sensors need to be very close to the factory location.

 

With the single sensor setup install it in the header collector on the passenger side, most headers will have a bung for it already.

 

Hi I'm trying to find long tube headers for my 89 f250 2wd 351w 5 speed that will fit. Not trying to spend alot of money.

 

Dekoda, check out Speed Daddy headers. They're 304 stainless steel and $188.00 for our 351w. I did read one person on here that complained of fitment issues where the tube had to be dimpled in a spot or two and a couple of welds grounded down to make it all work but I would expect that with such a low cost product. They look great though and shouldn't rust. Check to make sure they will fit your truck. These are for a 1989 F250 regular cab XL model b/c I didn't know the details of your truck but I would think it's about all the same

RACING SS MANIFOLD HEADER/EXHAUST 87-96 FORD F-150/F-250/BRONCO PICKUP 5.8L V8

 

The "Summit Racing brand" headers are a good option if you're looking to keep it on the cheap. They just give you Pacesetter headers for cheaper than you can buy the Pacesetters for. Be prepared to repaint them with better paint though, the paint they come with will flake off immediately.