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Headers and what to do with 02 sensor 1985 Monte

Posted By: WESTWOODSS

Headers and what to do with 02 sensor 1985 Monte - 01/30/16 11:30 PM

Hello guys and girls,
So I have an 85 ss that is Stock. I am removing air pumps and manifolds and putting in stainless long tube headers and a jones muffler system that I got from a buddy.
Here are my questions. Could use some tech advice.
I want to keep the 02 sensor so what do I do with it?????
and also. My car is an automatic which is most likely obvious.
Will these headers mount right in without taking all sorts of crap apart? Please advise me....
Posted By: Buick Runner

Re: Headers and what to do with 02 sensor 1985 Monte - 01/31/16 12:37 AM

For the O2 sensor you can weld on a sensor bung, use a clamp on sensor bung, or use a reducer with a O2 sensor bung.
Posted By: mmc427ss

Re: Headers and what to do with 02 sensor 1985 Monte - 01/31/16 01:45 AM

The O2 should be orientated between 9:00 and 3:00, top side of the pipe. Also you should wire and install a three wire O2.
Not familiar with the anything made by Jones.
Bob
Posted By: cj84ss

Re: Headers and what to do with 02 sensor 1985 Monte - 01/31/16 11:11 PM

If the headers are made to fit a g body they should go in easily. Usually the drivers side you can get the header in from the top. Just the AC and power steering brackets need removed and modify a little to work and add a few spacers to take up the space of the manifold. The passenger side usually goes on from the bottom. And a 3 wire (heated) O2 sensor is recommended as stated above.
Posted By: WESTWOODSS

Re: Headers and what to do with 02 sensor 1985 Monte - 02/21/16 10:24 PM

Just bought these flowtech headers. Was told they go RIGHT in. Without undoing motor mounts etc. I am still deciding weather or not to weld a bung for 0 2 sensor since I am removing air pimp etc. What do you guys think?
Posted By: 88ss408

Re: Headers and what to do with 02 sensor 1985 Monte - 02/22/16 10:46 AM

Are you keeping the ecu? If so you need the o2.
Posted By: Buick Runner

Re: Headers and what to do with 02 sensor 1985 Monte - 02/22/16 05:45 PM

The computer uses the O2 sensor to adjust the air/fuel mixture, without a O2 sensor your computer will default to full rich and gas wash the cylinders. You will need to install a O2 bung. The O2 sensor has nothing to do with the AIR pump. You could even just leave the AIR pump in place and just not have it hooked up to the headers, it only injects air into the manifolds when cold. Normally after warmup the air pumps injects air to the cat converter so it operates correctly. 3 phase cats need a rich and lean condition to operate.
Posted By: WESTWOODSS

Re: Headers and what to do with 02 sensor 1985 Monte - 02/23/16 01:08 AM

Ok you answered my question thank you.
I will have a bung welded in. Any advice on where it should go? I am removing pump and all hoses. It takes up so much space and looks terrible. I want to make the bay look nice. Not perfect just nice.
Posted By: Performance

Re: Headers and what to do with 02 sensor 1985 Monte - 02/24/16 05:28 PM

I just finished my project which is what you are doing. I welded my O2 bung on top of the driver side collector flange. You will need a new style heated O2 sensor for it to work properly.
Posted By: TooSlow406

Re: Headers and what to do with 02 sensor 1985 Monte - 02/24/16 08:46 PM

why not junk the computer? not sure about the rest of you, but my 85 is old enough to not have to do emmissions. so all of that stuff is junked. makes things a lot easier
Posted By: Buick Runner

Re: Headers and what to do with 02 sensor 1985 Monte - 02/24/16 10:41 PM

Converting to non computer opens up a can of worms, costs money, reduces MPGs, and no performance gain at best, often there is a performance loss. Plus it is still illegal under federal law to tamper with emissions in all 50 states regardless of antique, classic, or collector registration and age.
Posted By: TooSlow406

Re: Headers and what to do with 02 sensor 1985 Monte - 02/25/16 01:13 AM

still dont have to worry about it. i junked emmissions in my last monte and didnt have to worry about the test. same thing with my new one. we dont have to do those tests on cars as old as ours here. and im not worried about the fbi coming to look at it.

Also, i highly doubt the computer would make my 406 run as well as the holley i have on it.
Posted By: Buick Runner

Re: Headers and what to do with 02 sensor 1985 Monte - 02/25/16 03:29 AM

FBI has nothing to do with it, the EPA can just order Texas DMV to crack down on the scofflaws, they did it to CO.

You are talking about a non stock, racing engine instead of a factory street motor, apples to oranges, though I would not doubt a Qjet would offer better drivability and MPGs over a aftermarket generic spec Holley. Most aftermarket carbs like Holley are gas dumpers, with no thought for decent street driving, just wot for racing. Even the E4MEs can flow 750 CFM, there are members here who ran E4MEs on big blocks.

Seen alot of people here rip the emissions out of otherwise stock MCs and complain they run even worse after doing so.

Converting to non CCC you need a new carb which is a couple of hundred at least, then over another hundred for a non CCC dist, then a trans lockup kit which is a few hundred, then you need a wideband o2 sensor to tune this stuff which is another couple of hundred vs just keeping the CCC with a $14 bung you just weld on a header and be done.
Posted By: TooSlow406

Re: Headers and what to do with 02 sensor 1985 Monte - 02/25/16 03:55 AM

good thing about texas, we dont jump when the fed says boo.

racing engine? its a factory 400 thats been bored .030 over. ever heard of a 402 big block? this is a car i plan on driving on the street as often as i can. and race on weekends.

i rember when i put in my factory 400 in my first monte. ripping all that garbage off was the best thing i ever did. car ran a lot better than the 15s that stock cars run.

but you people can do what you want. i just dont like slow.
Posted By: Buick Runner

Re: Headers and what to do with 02 sensor 1985 Monte - 02/25/16 07:09 AM

That is why companies like Enron, love Texas. wink JK

You just admitted you built your 402 for racing. What is good for the track is often poor on the street and vise versa. As I said you are comparing apples to oranges as you have a non stock race motor in a heavily modified car vs the OP's near stock car and factory street engine. Not everyone wants to built a part time race car, especially since such a car is poor both on the track and street, Jack of all trades is master of none as they say.

I would hope a 400 would run better than a 305 as no factory 80'S MC came with a 400, again you are comparing apples to oranges here, a faulty comparison. Also we don't know the history of your car or its condition prior to you removing your emissions and 400 swap. For all I know it could have been a out of tune, hackjob, basket case, as many G bodies are ran ragged into the ground. It is no different if I took out a worn out SBC with Jerry rigged repairs and improper parts, install a fresh SBF, and claim that this proves SBFs are better engines than SBCs. You are using pretty faulty logic here.
Posted By: TooSlow406

Re: Headers and what to do with 02 sensor 1985 Monte - 02/25/16 10:45 PM

my 406 is for the street. it just so happens, since i drive a wrecker 24/7, that i dont need to drive it every day. so i can go a bit more radical with it. thats why no AC, no heater. Still has the rest, just nothing that will make it slower.
It probably wont be all that great. But I'm ok with running low 11s, high 10s. and still driving it all day long. No different than driving a 1955 chevy bel air.
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