un-needed and un-wanted smog stuff

[native-born-texan]

Hello,
I live in "no smog stuff" Nye county Nevada and every thing on my 300 six cyl. came from the factory in 1985 and I would like to remove it, including the exhaust system and put on a stock muffler. Is it possible to remove the pump with out harm to the engine it is not fuel injected, or just replace the exhaust. thanks

 

[Beach66Bum]

Since it's all factory and complete, I would leave it on. The engine is all set up and tuned to run with it on.

 

[native-born-texan]

I can do that but would it hurt to take the cat. converter off

 

[Beach66Bum]

I can do that but would it hurt to take the cat. converter off

No, it will not damage the engine. It may run richer and smell more at the tailpipe though. You may also get poorer mileage. The converter reduces the hydro-carbons emitted from the exhaust, it's just a pollution device. Being an older truck, it's not as sensitive as the newer vehicles when you omit smog equipment.

 

[native-born-texan]

I am getting 17 and 18 mpg so I better leave it alone, I am used to a 390 and two cherry bombs and I miss the noise

 

[Alvin in AZ]

I am used to a 390 and two cherry bombs and I miss the noise

I'd remove it for better power and gas mileage if it were mine.
There's a group that sez: "back pressure increasing the torque is a myth".

Here's how I did it for a v8...
http://www.panix.com/~alvinj/file12/BroncoY.jpg
http://www.panix.com/~alvinj/file12/BroncoY1.jpg
http://www.panix.com/~alvinj/file12/BroncoYa.jpg

The four grinding wheels are called "plugs".

Made the two extensions for the hand grinder using 5/9-11 coupling nuts
and short chunks of 5/8-11 grade-8 bolt and 1/4-28 set screws.

The sound...
45" straight through Walker/Thrush muffler.
Looks like a Cherry Bomb on the outside but ain't crappy on the inside like
Cherry Bombs are. It's 2+1/2" all the way through, no intrusive pimples.
YMMV?

http://www.panix.com/~alvinj/file12/Bronco2wd.jpg (Bronco)
http://www.panix.com/~alvinj/file12/exhaust1.jpg (old stuff in '75 F150)

Alvin in AZ

 

[native-born-texan]

Hello Alvin
That is fantastic, thanks for taking the time to answer , could you tell a difference in performance?

 

[Alvin in AZ]

...could you tell a difference in performance?

Not in my case because I never drove it before I'd tore it apart for the ZF swap.
I bought it abandoned and while waiting on paper work I tore into it.

What I did notice was the improved(!) gas mileage after the 4 degree timing
advance using a Cloyes timing gear. That also lowered and smoothed out the
power band and that made the rig more drivable with the manual transmission.

----------------

But I did notice a big change in power when years before I'd opened up the
Y pipe on the '75 F150...

http://www.panix.com/~alvinj/file12/exhaustY.jpg

It was like adding a couple cylinders to the 360FE. The hole Ford put in the
side of the pipe before adding the side branch was a ragged torch cut hole
shaped like a football and maybe a golf ball could've been stuffed through it
if you first ripped its cover off?

It sucked donkey dick.

Alvin in AZ

 

[Beach66Bum]

Very nicely done!!! straight, clean, factory look, awesome

 

[Ridgerunner]

Very nicely done!!! straight, clean, factory look, awesome

I have to agree. Very well done.