Breaking up at highway speeds

[KillerBee1972]

This might be an easy fix but i just dont know anymore. My head might be just thinking too much. but anyway i had a hopped up small block in my charger and was just got tired of the big cam and constantly having to re time it etc. so i ended up finding a 340 and put that in its all stock except for the rpm air gap intake and eddy carb 600cfm, and headers. now when i would rev it it will pop through the pass exhaust off and on. not all the time. i have checked the timing its right on, checked fuel and its getting plenty its not lean or too rich, i am leaning towards the points set up that i still have in the car... im just not sure at all, because in city driving the car is great no problems its only on the highway when i will give it some to either pass a car or just enjoy the car when it will start sputtering, break up, and just darn right tick me off, like i said i might be looking too hard and just not seeing something. please let me know what you all think.

thanks
Scott

[Chryco Psycho]

I assume you have the vacuum advance connected , generally I set timing at 36-38* at 3000 rpm & either use an allen wrench & dial out most or all of the vacuum advance , insert the allen wrench into the hose nipple on the dist or just disconnect the vacuum advance & leave it off . it may be over advancing & popping in the exhaust .
if it is on deceleration it could be an air leak into the pipes

[elacruze]

Every Eddy carb I've seen is too lean right where you describe your troubles. I never adjusted one, I tossed them and put a Holley or Q-Jet.

Deceleration popping is usually an air leak coupled with too-rich idle mixture. Typically people richen the idle mix to try to compensate for the lean low speed jetting with Eddy.

Acceleration miss can also be a weak ignition/wires/crossfiring distributor cap under load. Since you still have points, I'd look there first-if you keep them, find somebody with a proper dwell meter so you can set them up optimally. Insufficient dwell weakens spark and worsens with RPM.

[KillerBee1972]

i do not have the vacuum advanced hooked up, if i remember right when it was hooked up the idle wouldnkeep on rising, but then again that was on the other motor so i will mess with that right now, and would you recommend that i swap over to an electronic ignition?

thanks for the help so far Chryco Psycho and elacruze

Scott

[elacruze]

Electronic ignition is a lot easier to set up (that is there is very little setup or maintenance) and kits are inexpensive since Chrysler used it stock stuff. Unless you have some specific reasons to keep the points (Money, originality, or just to say you're able to dial them in) I'd toss them in the toolbox and go electronic. I use a stock Chrysler setup in my own car.


Start out by checking that the point contacts are clean and smooth, and they open about a business card thickness (15 thousandths or so). That will get you close. Verify that your connections are good at the distributor and coil, and that the condenser is not loose or has a dirty wire. Be sure the inside of your distributor cap has no black trails, if there is black dust in it carefully blow it out and rinse it in soapy water before wiping it and rinsing with clean water. Loose carbon can be embedded in the cap if you just wipe it out, and spray chemicals don't do much to help.

[KillerBee1972]

ok thanks for the info i will probably go and convert to electronic, but however i did end up hooking up the vacuum advance and noticed a big change, the hesitation and sputtering went away while i would get on it, i didnt get to try it on highway speeds but it definately helped out alot there is still a little gremlin in there still somewhere the car is still just not the same but hopefully i will figure it out.