340 popping through carb at low RPM.

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What carburetor is on this? Sounds like a lean pop.
 
I'm guessing a lean pop. However, hard to hear it in the video with the road noise. Will it pop in neutral? IF so, a video from under the hood with the air cleaner off would be more definite
 
You need to remember something. The 1406 gets a LOT of press, but IT IS NOT a performance carburetor. It is an economy carburetor and is calibrated as such. The 1405 is the performance tuned version.
 
RustyRatRod said:
You need to remember something. The 1406 gets a LOT of press, but IT IS NOT a performance carburetor. It is an economy carburetor and is calibrated as such. The 1405 is the performance tuned version.
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agree, and I'll add usually even the 1405 will need to be richened a tad, at least by my experience
 
It's got 7547 rods in it now. It pops while revving in neutral as well.
 
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Matrick69 said:
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That is strange
IMO I still say that you most likely have a lean condition on the primary side of the carb.
Look for Edelbrock's tuning guide on their website, it's pretty easy to do.
You will become a student of reading spark plugs.
Good luck
 
7547 are the leanest rods available.

Make a pretty big change to be sure it’s enough difference to matter.

Something like a 7042.
 
PRH said:
7547 are the leanest rods available.

Make a pretty big change to be sure it’s enough difference to matter.

Something like a 7042.
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I am going to have to pick some up tomorrow. All I have is a set of 7347s from another carb. I threw them in for the heck of it and am about to take it for a drive.
 
bcschief said:
Also inspect the valve springs you may have a broken one.

Brian
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On my list of things to check! I did a compression check on it this morning and they were all close. Lowest was 135 and high was 142. The metering rods I have made no difference. If I get a chance this week, I will pull the covers and have a look .

Thanks
 
Did you get that burned intake valve checked out yet?
 
Try a different carb if you know someone who will borrow you one. Then try a different distributer to rule all that out.
 
Well I finally had a little more time to play with the car over the weekend. I started with the richer carb jets with absolutely no change. Removed valve covers and watched all the rocker arms move. They all seem to be moving about the same distance just by the eye test. I then backed off all the rocker shaft bolts to make sure the valves were closed. Pressurized each cylinder and verified no valves are leaking. All valve springs are intact. Put it back together this morning with a different cap, plugs, and plug wires with no changes. Played with the timing a bit and can make it better by advancing it til its hard to start and retarding slightly. At this point, its much better, but I start getting the exhaust pop back at idle. I did this without the timing light today, but have a mark from previous so its in the ball park. Starting to wonder if I should remove the intake and inspect the cam. If it is worn, would it be noticeable on the rocker arm movement?

Thanks for the help guys.
 
Just wanted to update everyone who helped! Replaced my unilite distributor with a Mopar performance kit and ALL my problems are gone! Thanks again for all the input, it's much appreciated. Sooooo glad I'm done chasing this issue. The car runs like a dream!
 
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