Base91

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Anyone know? In California can you swap a 3.4 for a 3.1 legally (title update?) and then use the 3.4 headers legally because they are CARB approved? If so just how much "massaging" is required to make the 3.4 headers fit a '91 F'bird? Or could the 2.8 headers have the AIR port added so it all at least looks legal?

Kevin91Z

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I dont know if the exhaust ports are the same on 3.1 heads vs 3.4 heads, but if they are, you can swap a 3.4L engine into your car with no trouble. Then you can use the 3.1L headers. Just dont say anything to the smog guys. They'll never know the difference. There is a tech article in the Tech Articles section from the front page of this website that describes the process.

Pillsbry10

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yes the heads are the same

problem is if you use smog approved 3.4 headers the number on the headers will reflect that its a 3.4 and not the original engine wont it? they do take a good amount of massaging to get the 3.4 headers to work.

you cant just put the whole 3.4 in the car as its not original equipment, you might could get away with it with EVERYTHING from a 3.4 car but i doubt it

Awesome-X

The heads on the 3.4 are exactly the same heads that are on all the 60v6's (2.8-3.4) so they would work just fine or you could probably just add that AIR port and they probably wouldn't see the difference. I'd go with the cheapest option

KG427KG427

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link to these California legal headers ? and they will fit on a 3.1 or 3.4 correct

Kingsobieski

3.4 has 02 sensors in the exhaust manifolds. 3.1 has a single o2 in the y-pipe. You'd need to have the holes sealed up where the o2 sensors go.

Base91

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Headers are Pacesetter 70-1206 but they are only legal for 2.8. Strictly speaking.

KG427KG427

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Kevin

Do you know any1 or any1 from California? Willing to install headers on my 3.1? Let me know the price and how long I would need to leave it

Kevin91Z

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You'd have to talk to Dyno Don.

KG427KG427

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Ok ill try I thought he was v8 guy only

KG427KG427

iTrader: (1)

Ok so just have to fill up the whole on the 2.8 headers.

Is heat an issue and my car is a daily driver will this kill my mpg ??

I can tune it I have moates chip thing fasteddi burns for me

Kevin91Z

iTrader: (1)

Don does many different things, and exhaust is one of his specialties. I know he doesnt have any room now if you're in a hurry, but he might be able to recommend someone else.

No, headers do not kill your gas mileage. If anything, they will help as the exhaust gas from each cylinder has its own tube to travel in instead of being bunched up in the small stock exhaust manifold.

KG427KG427

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I am in no rush, but would like to schedule something what is the best way to shoot him a message to get a responds at his convenience.