91 F250, 302, 5 speed. Has factory replacement exhaust manifolds, and exhaust from cat back is new. Only use it for a occasionally daily driver, and tow a light travel trailer a few times a year, mainly to and from hunting camp. Should I look at headers into a new exhaust? Any benefits? All emissions system is in good shape and works well. Not looking to delete any of that, just wondering if I can get slightly more power, and better mileage with a new exhaust system.
Thanks

 

Headers and exhaust will help but it's just going to be a relatively mild hop up, the real improvements would come with a cam change.

 

Forgot to add, motor had been rebuilt, punched. 030 over with a slightly hotter comp cam.

 

What cam? Headers and Y pipe will definitely help with just about any aftermarket cam, even shorties are an improvement.

 

Dont remember the cam part #, but, it was a comp cam recommended by several others here. Wondering about a complete header exhaust package, deleting the cat, and how that woumd work with the smog pump. Since all emissions are working fine, just wondering about deleting the cat, and going to a straight header and exhaust.

 

If the stock cat goes the air pump and all associated hardware serve no purpose and can be deleted to. The computer will see this but it won't make any difference in the way the engine runs.

 

Reviving kind of an old thread I posted. But, here goes. I am considering a complete exhaust retro fit. From manifolds back. Looking for a little more power, and mpg. How do I make this work with my current emission/smog pump setup without bad run ability, or throwing codes? Do I discard the O2 sensor and cap all the vacuum lines? What do I do?
Thanks everyone.

 

Paul answered that question the last time you asked.

The EEC-IV (OBD-1) computer looks at the upstream oxygen sensor to adjust the fuel injectors. You cannot delete the oxygen sensor and expect the computer to know how well it is adjusting the fuel mixture. There is no downstream sensor so the computer does not know if the catalytic converter is still there nor does it care. I used shorty headers, y pipe into a high flow converter and a chambered muffler with dual outlets. Another option is long tube headers and then have a shop fabricate a dual exhaust system with or without a crossover pipe.

I deleted the air pump on my 302, installed an idler pulley in its place and followed the rest of the delete procedure spelled out in one of the many threads about this topic.

 

If it needed to be done, headers to an H pipe with the O2 sensor bung in the - of the H would replicate what the current setup is seeing (I'm assuming a '91 had the single 02 sensor).

What you are looking for is as you've been told, a Manifold/Cam/Header setup to get what you want. By the time you do all that you'd be better off just building a whole new mill on a 351 block with an aftermarket FI system.

Not worth it if all you want is a little more power and better MPG.

You'd do better to just keep what you have in proper tune.

 

how much hp you looking for, cam should have been noticeable change? how much are you willing to spend, for a little more hp, if 2wd gears would be best bang for the buck, depending on what its geared now. JY swap very cheap, you need torque to move that F250 with a 302, not hp

 

What does that have to do with the topic of the thread? There is a Marketplace section for buying and selling.

 

That post was removed.

 

Thanks!...