I have a 1977 f150 with a 351m and stock 2 barrel, nothing but
trouble. Edelbrock seems to have a package for my truck, I don't
know if I need a EGR or Non EGR combination. I'm tired of tapping the
carb with a screwdriver. How will cold weather effect the preformance of a 4v carb with choke in the winter?










1972 F100/302/C4
1977 F150/351M/6C
1978 BRONCO /400/6C
2002 F350 PSD

:-)

 

if you have to pass emissions testing then get the manifold w/ egr. i do and thats what i did. xsept i got a holley. it all depends on what your looking for, holleys deliver better performance but are sometimes troublesome to keep set up properly, and edelbrocks deliver good gas mileage and are easier to set up. witha properly working choke it should have no problems in the winter provided the truck is set up for winter so the will be no carb icing and such. good luck.

1977 F250 460
C6 Hedman Headers
Dual 40 series
edelbrock performer
holley 4160
msd 6a and blaster coil

 

hi
it should actually be better in the winter because of the performance upgrade. i'd go with that performer kit. I like edelbrock because it is easy but also seems to be more reliable in cold weather. there are certin parts in the holley carb that like to get stuck and your truck won't run right. in perfect race conditions holley is a little better. i have the #1407 carb and it is nice!

 

Get the Edelbrock package with EGR unless you want to do a bunch of ignition tweaking. The 1406 600cfm electric choke is easy to set up.

I like manual chokes if you can use them properly. The electric is nice if you don't want to bother with remembering to shut it off.

 

I already picked up the intake manifold for the non ERG. How much
ignition tweaking is there involved in the set up?

 

Just watch out for part throttle ping. Your vac module may need to be changed or adjusted.

 

I too have a egr valve and wish to upgrade to a 4bbl. Having done this swap before(but a good while ago) I know some of the problems involved. My question is what the heck is a egr valve for?? How does it work? Why is it on a 1978 400m? How much does a good intake and carb cost?

 

OK, An EGR valve reduces the oxides of nitrogen (NOx) that your motor produces at part throttle cruise. At part throttle lean cruise the temperature of the combustion gasses goes up to the point that the nitrogen molecules in the air are broken and combined with oxygen to form the stuff that is a big part of smog (NOx). The EGR valve opens under these conditions and admits a small quantity of spent gas (no oxygen) from the exhaust into the manifold which causes the combustion mixture to burn more slowly and therefore it does not get as hot. This of course keeps the nitrogen molecules from being broken down. Kind of like adding some octane:-) -Not really. Of course this slower combustion process needs a little more ignition advance to get maximum power so the OEM tailors the advance curve by modifying the vacuum signal with valves and orifices etc. to the vac advance mechanism and modifying the spring rates and start stop points in the vac module. These modifications vary with year, engine, and manufacturer.

The operation of the EGR does not reduce the HP that your engine produces since it only operates at part throttle. At anything above just a light throttle the valve closes and the engine operates normally.

When you remove the EGR valve the engine of course produces more NOx and the faster combustion can cause part throttle ping while cruising. The modifications that are required to reduce the advance at part throttle will vary with the system used. Which as I noted above varies with the year, engine, and manufacturer, even the calibration for that engine.

The cost of a carb and manifold can be found at Summit, Jegs, or your local part store.

 

Thanks for the info. Will the pinging wreck the engine if not
taken care of right away?

 

YES, It beats up the tops of the pistons and can cause fatal damage if not stopped asap.

 

Thank you...thank you very much. I understand now why not to disable the egr. Isn't the pinging also called pre-ignition knock? Slaps the valve closed causing the pinging sound? Also caused by not enough octane or bad gas?

 

So, do all trucks have this EGR by default? I have a 77 F-150 4x4 and don't know if mine has it or not. How do I find out if I need the EGR carb/intake when I upgrade this winter? That's something I plan on doing soon.

 

What size of motor?
Not to sway to far, but, what port should the EGR be hooked up to. (full vac, intermitant vac,?) 78' 400

 

Lets see, answer you guys one at a time...

Bentkey-
Pinging is similar to preignition but they can have different causes.

Pinging is not the sound of the valve being forced shut. Ping is a high pressure explosion causing a pressure wave to slam into the top of the piston. It is kind of like taking a small red hot ball pein hammer and hammering on the top of your piston. It will sooner or later bash a hole thru the top due to softening of the aluminum and the impact. Pinging is caused by the fuel mixture burning to fast vs the position of the piston. The quench chamber head "squish" high velocity gas breaks up the pressure wave formation in the combustion chamber and helps the mixture to burn more smoothly.

Preignition is a premature ignition of the fuel/air mix caused by a hot surface. It could be a red hot particle of some combustion chamber deposit, or a sharp edge or burr on the head, or a hot spark plug electrode. This preignition can occur at any point in the combustion cycle and can cause severe damage to the engine. The reason you polish the combustion chamber is to remove the sharp edges and make the surface "slicker" so it won't hold deposits as well.

More octane can help pinging but usually does not eliminate it efficiently $$$. A small timing curve change is usually the solution.
Bad gas is usually just gas that has lost some of its components in storage lowering the octane rating.

Ken2600-
A 77 F150 should have an EGR valve. Yours may have been removed tho.

1hdman-
The EGR because of its function can not be hooked up directly to a vac source. There is a whole series of valves on the 400 that controls it. You will need to get a vacuum diagram for your truck and a bunch of parts to hook it up correctly. The online store may have the sticker but you will need the shop manual to identify the parts.

Hope this helps a little...