74Runneer

I have a 74 318 that i just finished going through the heads and intake (both new). I have a 600 cfm eddy electric choke carb. last year my roadrunner liked to bog out right in the middle of an intersection, or right when i try to show off doing a burn out..... awkward.... Anyways I'm thinking this is a carb problem, perhaps the jets? Ive used all the canned stuff you put in the tank and that helped but the problem is still there. Some people just tell me to keep on driving it and it might go away and others say rebuild it. All my vacuum lines seem good. Im not sure what else it could be because according to the manual Im not flooding it or leaning it out so im stuck. What do you guys think?

And if the answer is rebuild, is this something that i should just take in to get it done professionally, or can a learning, somewhat mechanically inclined 18 year old do it? Id like to learn more about the carb if i could but i want whats best for my car.

Coronet 500

If you search You Tube "Rebuild Edelbrock Carb" you'll get a ton of info, and after review your decision should be easier.

Silverick

An Edelbrock carb is one of the easiest carbs that I ever rebuilt. You can do it!!

Archer

74 -

The rebuild shouldn't be that hard, but unless you have an aftermarket cam and full exhaust in there, 600 cfm may just be too big.

Archer

Gorts 5th

X 2
get a tuner kit for your carb the assortment of jets rods and power springs will help you adjust your air fuel mix you will have to downsize the jets and or install larger rods maybe even a power valve spring..
You may be getting enrichment to early or you're just over jetted .

74Runneer

Yep, I have something similar to a 340 cam, and headers to duals. Is the tuner kit your talking about the $50 carb kit that I could get from napa? I believe it has floats, springs, and gaskets.

Gorts 5th

check it out
thats the tuner kit

74Runneer

I dont think thats what I was thinking of. How much is that?
When it was runninc crappy last year, it had a single plane intake and stock heads. Would upgrading to a duel plane, and getting 302 heads help this?

jacilynn_s

the 74 318 was a low compression engine that came with a 2 barrel carburator. Putting 302 heads on the engine will lower your compression even more. A cam will not fix this.

Your *new* intake is it aluminum? Cast iron? did you leave the cross over passage?

A bog on this engine would be norm since you put headers on it. The intake is COLD the fuel will not stay in suspension which is what causes the bog. Stock exhaust has a heat rizer valve for this reason. The crossover passage on the engine warms the underside of the intake so that the fuel stays in suspension.

Start engine let it get good and warm *about 10 minutes running* turn it off and leave sit with hood closed for about 5 minutes. Then start it again leave idle for 3 minutes and go for a run if your bog is gone that is your problem. Not much you can do to get around it either.

440roadrunner

The 318 heads are fine for a mild street engine. Here's an example of a quickly modified, low buck setup that is fairly snappy considering the money into it, all of it used parts off Craigslist except the headers.

Used 200.00 Craigslist 318 from mid 70's. This completely stock engine had never been apart, (original blue painted gaskets) had been in dry storage many years, and was claimed less than 40K miles by the seller. After running, a week, and tearing down to change the cam, it was evident that it MAY have had less than 20K judging from no--wear on the cam, lifters, and plastic cam sprocket.

SO-------------

We have Hedman headers, as the original 273 Dart manifolds are pretty small, the only new part I bought other than gaskets, motor mounts, etc

All used off Craigs............

Ed Performer RPM intake, 75.00

Ed 650 carb, about the same price

Old cam I have "about the same" grind as the old 340 "stick" cam in very good shape, and yep, marked the original lifter locations.

Used factory look-alike performance Accel breakerless distributor, with about 20* curve. Initial timing at 15-17*, so total WOT is 35--37*

This thing is VERY snappy, has fairly good low end punch right off the line CONSIDERING "what it is". The converter is "junk." That is, it's out of a "junk" 3/4T van and has a stall of about "less than 2K RPM." So the converter kills off ANY low end

With a 3.70 rear gear and tall tires, RPM at 70 is about 3200. Mashing the throttle for about 3 seconds at 65 and watching the GPS results in over 85 mph, just like that.

Freeway ramps are fun again.

74Runneer

302 casting heads have a smaller cumbustion chamber then stock because they areclosed chambered. So they actually increase compression to. 8.5-9 to 1. On top of that I had them milled a little. So my compression should be fine. My intake is an aluminum edelbrock performer. I havent put the intake on yet and havent pluged the crossover passage, and using your advice I probably wont. I dont think denonation will be a problem in minnesota, with a cr around 8.5 to 9.

Ill definetly try the 10 min, 3 min warm up test after I get my heads and intake on.

jacilynn_s

if you milled off .020-0.040 off the heads they would be fine stock they were a little lower compression even with the closed heart shape. Not sure why chrysler did that but they did. Ran into that problem on another engine ended up taking the heads off and taking 40 off then put thin squish gaskets on them.

74Runneer

Well they are supposed to be a noticable amount smaller but there was just a large variance in the castings, you must have gotten a bigger pair. Ive heard great things about the swirl ports.

So back to the carb, how much is that tuner kit? Could this just be a timing issue?

Coronet 500

To 74Runneer, the 302's will raise the compression .5-.75 of a point on that year of engine, any milling would be more. Your compression is fine, your manifold is a perfect choice and I would leave the crossover open. Look into increasing your accelarator pump travel (shot) first, a simple linkage change may be all that's needed.

Your ignition timing could be adding to the problem, if you have a timing light tell us what your initial is and your full mechanical advance and at what rpm and we'll give you a hand with that.

Moparod

I ran an identical setup in my '36, 318 with a repro 340 cam and headers. Difference is I used a dual plane M1 intake. Dual plane intakes are generally better suited for low-mid rpm range engines, single planes more for mid-upper rpm ranges. Mine was a great runner with none of the issues you describe. I'm using the same intake and carb on my new 360 crate. I may have to fatten the carb up since the 360 is not only larger but also a considerably hotter engine build-wise.

I just rebuilt my carb to clean out the old varnish residue from two year old gas. Easy carb to do, took me longer to clean it than the disassembly/reassembly. Just be mindful there are small parts in there and its easy to forget where something came from. Lay out the parts in the order you remove them, if necessary take pictures before you remove something so you won't forget where it came from.

moe7404

warning. on carter AFBs or a eddy copy. if the jet doesnt come easy DONT force it. if it strips out the last thing to do. is put a small torch heat the jet till the flame color changes. then dump water on the jet. it should come out now.

Skwerly

man, when a buddy and i rebuilt the stock 2bbl that came on my sixty eight, the thing idled at least 30% louder than it did before. it was sooooo weird.

Moparbob

I've seen this before !
VERY surprising what even the low-pop 318's will do with Heads, Cam, Intake & Headers, and some attention to detail, they can REALLY come alive !
I've even seen some with 2.02" 340 J Heads added, which made the compression even LOWER, that absolutely screamed.

74Runneer

Coronet500 - Okay, yes i do have a timing light. When i get my heads and intake on, ill let you know about all my timing specs so you can help me out. Ill get my timing all figured out and if it still have that bogging issue then ill have you guys lead me from there. Im thinking ill have to rebuild the carb because the car had been sitting for about 8 years, and last summer i brought her to life again. So im sure its all gummed up. As for right now, im just waiting for my machine shop to finish up doing a valve job and milling on my heads. Ill probably gasket match the exhaust and polish the ports a little. Im not going to go near the bowl or do any major porting just a clean up.

Thanks for all your help!

74Runneer

Why would it do that????

Coronet 500

Hey you bet. This would be a good down time to clean your tank and fuel lines if it has sat for that long. It will be the next problem you have.

74Runneer

Yeah my fuel gauge doesnt work so ill have to figure that out too

moe7404

the thing good is that an eddy is easy to tune. the bad thing is they ALLWAYS needs tuned. a carter from chrysler is tuned from the factory for a certain engine. a lot of people talk about tuning, but few can do it. most eddy carbs have a rods that have a step from the small step to the big step that is to big. look in your chrysler AFBs the rod steps are smaller than a eddy carb. and ONLY change a jet OR a rod, if you change both you cant guess what your change is. ALL so a change on the jet of .001 is a bigger change than .001 on a rod. cause the rod is smaller in dia.

Skwerly

I haven't a clue, but I imagine we forgot something or did something real wrong.

The old mans garage

I have had this issue with bogging or dead spotting, usually it turned out to be a worn accelerator pump in the carb. This comes with the rebuild kits.

74Runneer

I'm finally going to tackle the rebuild tomorrow and monday. I sure hope It came with a new accelerator pump! Ill check to ssee if that fixes my issue and if it doesn't ill go with smaller rods.

Coronet 500

One suggestion,which applies to any "tuning", make one change at a time to see the result of that one change. If for example you were to change anything during the rebuild you may not know if the rebuild or the change corrected the problem. Good Luck.