Quadrajet on AMC360

[jakerc02]

I'm planning on putting a quadrajet carb https://www.summitracing.com/parts/sum-250216 on to an edelbrock performer manifold, and I have a few questions of the details of it. First is would the stock throttle cable work or would I need an adapter like the one they sell on BjsOffroad https://www.bjsoffroad.com/Carburetor-T ... p_667.html? Next I have an electric fuel pump, but I'm not sure if it will put out enough fuel pressure to work with a four barrel. Anyone know what kind of fuel pressure these things need? I only get around 3-5 and it kind of bounces around. My next question is regarding if I should get an egr or non egr performer manifold to work with this carb. Also I'm guessing that it wouldn't work with the vapor canister so would I just have to delete it? Sorry for all the questions, I just don't want to order some majorly wrong parts.

[tgreese]

Don't know about the rest, but something about vapor recovery. What year is your Jeep? If you have the later "active" canister design, the fuel tank connection will still work. The earlier "passive" designs rely on a connection to the air cleaner snorkel. That too can still work if you keep the factory air cleaner. If you have the passive type of canister and want to change to an aftermarket air cleaner, you can substitute the later style canister and plumb it as in the later vehicles. Again, this is for recovery of fuel tank vapors.

You will probably lose the float bowl vapor recovery, unless the carb you choose was originally designed to work with vapor recovery and you use the factory air cleaner. You need both the connection from the float bowl to the canister, and the vacuum operated door in the air cleaner snorkel for float bowl vapor recovery to work.

Regarding EGR, it depends on what you need to be emissions compliant at your locale. You understand that EGR is an emissions device? You might be public spirited and want to keep the EGR for lower emissions, even though you aren't required by law to have it - then you'd need the EGR manifold. It seems unlikely the law would allow this carburetor swap while requiring you keep all the existing emissions devices.

[jakerc02]

It's a 79 and had the canister routed to the old 2150 carb. I'm exempt from emissions where I am located, but had heard that egr was good at lowering engine temps and just helped over-all.

[tgreese]

A '79 has the "active" canister. You can plug the line from the carburetor float bowl and still have vapor recovery for the fuel tank.

The EGR valve mixes exhaust gas with the fuel-air charge. Exhaust gas is basically inert (depleted of oxygen), thus dilutes the charge and lets it burn at a lower temperature. At high enough temperatures, the nitrogen in the air burns and makes nitrous oxides (NOx), which forms a major part of photochemical smog. Lower combustion temperatures makes less NOx. I believe a dilute charge can also be leaner, additionally reducing unburned hydrocarbons (HC).

Only the combustion gas temperature is lowered, not the engine temperature. Power goes like fuel burned, and the same amount of gas will produce the same amount of heat. I don't think it makes much difference in the coolant temperature, if that's what you are expecting. Possible cooler exhaust gas will transfer less heat to the engine... maybe.

Might be that, when you run the original carburetor and remove the EGR, the mixture is now too lean. Too lean runs hot. Possible that's where this claim comes from.

Since EGR mostly shuts down at low vacuum, I don't think it makes much difference to engine power. I also don't see much advantage beyond lower emissions. You'd need to tune the new carburetor to work with EGR to get this advantage.

[Stuka]

EGR has been proven to make no difference at all in power since its not active at WOT as mentioned above. So no real reason to get rid of outside of simplifying things a bit. The engine can actually cruise more efficiently with it in place.

However, nobody makes a QuadraJet intake for an AMC last I checked. The stock 4v intake uses a ford pattern for the MC4350. And after market solutions like the Edelbrock performer and RPM are square bore.

[jakerc02]

I plan on using an edlebrock performer intake with an adapter to make the QJet work. I know that the edelbrock 1406/1400 600cfm carb has a separate EGR and non EGR version. Is there anything like this for the Qjet, or would it just need a slightly different tune to make the EGR work?

[Stuka]

I plan on using an edlebrock performer intake with an adapter to make the QJet work. I know that the edelbrock 1406/1400 600cfm carb has a separate EGR and non EGR version. Is there anything like this for the Qjet, or would it just need a slightly different tune to make the EGR work?

The 1400's EGR port just makes it simpler to activate it without having to worry about the OEM EGR setup. However it ignores engine temperature, and really is just ported vacuum under another name.

You can make any carb work with an EGR, you just need to use what came on the Jeep. Which is basically a CTO that turns ported vacuum on and off for the EGR. The CTO makes sure the EGR doesn't get enabled until the engine is warmed up.

[Dr.Bob]

I plan on using an edlebrock performer intake with an adapter to make the QJet work. I know that the edelbrock 1406/1400 600cfm carb has a separate EGR and non EGR version. Is there anything like this for the Qjet, or would it just need a slightly different tune to make the EGR work?

Yes; carburetors calibrated to work with EGR have a much leaner part-throttle mixture, since the cylinder is partly filled with inert exhaust gas in place of combustible atmosphere. A Quadrajet with an original factory number beginning 170xxx tends to be calibrated with thicker primary metering rods to attain that leaner part-throttle mixture. The 70xxx series carbs tend to be from before EGR, so they have a thinner primary metering rod that would result in the mixture being too rich at part-throttle with EGR operating.

The secondary systems are the same, since as noted above the EGR is inactive at wide-open throttle.

Your best bet, if you are trying to run an EGR system, is to start with a 170xxx series carburetor from any GM application with a 350 motor; the Olds version might be easiest to adapt, as the fuel-filter outlet points straight forward, whereas the Chevy and Buick point to the passenger-side, needing a 180' bend to reach the fuel-pump.

Oh, and 3-5psi is all you need; you're not pressurizing anything, you're just refilling the float-bowl so there is enough fuel to leak through the jets.