2bbl to 4bbl with emissions

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Dec 19, 2002 | 12:27 PM

bluemustang

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From: Columbia, TN

2bbl to 4bbl with emissions

I was think of going to a junkyard and getting another intake for a 4bbl to put on my 75 f100 390. I was told that was not a great idea because I have the emission stuff on my truck and that the engine was setup for it. I read that if I whiched over to a 4bbl and removed the emission stuff that the engine would not last as long because of the way the engine is setup. Does anyone have any input on this and what I could do.

Thanks David

Dec 19, 2002 | 03:23 PM

woppini

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2bbl to 4bbl with emissions

If you dont have emission testing where you live, i cant see why putting on those items would cause a problem. Basically your just letting the engine breathe better. 2 things that will kill an engine with the things you are putting on would be detonation (pinging) or a too lean condition. Double check that your timing is ok, and that your mixture is set proper, and you should be ready to go. Remember, in 1975 there wasnt much in the way of technology for lower emissions. Basically retard timing, (cam and dist), and lower compression ratio. Some had smog pumps as the years went on.

Dec 19, 2002 | 07:31 PM

Franklin2

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From: Virginia

2bbl to 4bbl with emissions

Like the other poster said, running too lean can cause pinging and ruin the engine. One of the common causes of this is installing a carb that is designed for an EGR system, without the EGR in place. If you are going to buy a new carb, get one that says "not for emission controlled vehicles". This type of carb will be jetted for use without the EGR and will not give you engine problems. Of course if you hook up the EGR, you can run the emission type carb.

Dec 20, 2002 | 03:56 AM

DailyDriver

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From: Bakersfield Ca.

2bbl to 4bbl with emissions

If you have the smog equipment on now, you will have to have it on if and when you have to have a smog test. The only difference is the extra two holes in the manifold. The EGR set up should be the same. You will need the 4v EGR plate and just hook it up just like the 2v and get a carb. to match. If you don't have to pass a smog test then it's no big deal. It won't hurt anything to go with a non emissions set up for your year. Get a 4v non EGR manifold and a non emissions carb. If you can't find a non EGR, use an EGR manifold but be sure to get the EGR plate with the manifold anyway even if your not going to hook it up. You will need it to bolt the carb. onto and to block the exhaust gases from the manifold from burning up your carb. and blowing exhaust gases back up through the carb., or you can use a carb. spacer. You can get a spacer from any auto parts store. Remember, do not bolt your carb. directly to an EGR manifold. Use the EGR plate or a spacer. Good luck.

Dec 20, 2002 | 08:02 AM

bluemustang

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From: Columbia, TN

2bbl to 4bbl with emissions

Thanks everyone, I do have to pass emission but only the tail pipe test. I only have the egr spacer plate under the carb. If I get a 4bbl card that's "not for emission controlled vehicles" and get just a regular spacer will it still pass the exhaust tes? Does the "not for emission controlled vehicles" mean for like calf. were thay look under the hood and test everything?

Thanks

Dec 20, 2002 | 07:18 PM

Franklin2

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From: Virginia

2bbl to 4bbl with emissions

If you have tailpipe checks, then you had better get the egr manifold, and the emission type 4 bbl. It will be jetted differently and have all the little ports you need to hook all the hoses up.

Dec 21, 2002 | 01:30 PM

cjcathey2002

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From: USA

2bbl to 4bbl with emissions

emissions testing is quite odd. i live in california, and last aug i put a new holley carb on my truck. my egr hasnt been working for about a year due to the vacuum amplifier on the pass side valve cover not working. any hoot, my truck is running really good right now, so i took it the emisiions testing place in AZ where i was going to register my truck. passed the loaded test with about 50 percent of the standard allowed emissions. the only problem was i couldnt get my idle down low enough to pass, guess i have some more adjustments i need to do. they looked under my hood and everything. they must not do a very good search beacause i have everything there but most of it is not working or not hooked up. but in regards to what has been posted above, what worked for me was to just get the carb that is for non emissions controled vehicles. then make sure the rest of the engine is tip top and running really good, then have a mechanic with the right equipment adjust the idle to pass and you sould be fine. i have heard that the heavier the truck the more emissions they allow, mine is a 250 so if you have a 150 or 100 it may not work, but good luck anyways.

1977 F250 460
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edelbrock performer
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