cant get pinging to stop.HELP!!

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dart gt

dart gt

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i have a 70 340,268 comp cam,600 edelbrock carb,stock heads and virgin block.Motor was rebuilt last winter.car runs good until you floor it then the pinging starts,sometimes it will ping going up hills.tried other carbs,no good.i run octane boost,no good.tried lead suppliment.no good.i burn high test gas also.called comp cams and they told me to time it 14 initial 35 overall.i also curbed my distributor.no good.can anyone please help.at wits end.thank you David
 
Did you tune the carb? What is the ignition curve? Edelbrocks are typically lea out of the box, and the step up springs are not usually right.
 
compression is 10.5to1 and premium fuel.i tried step up springs,4 barrels open sharper but still pings and blows black smoke.called eddys teck line and they told me to put a 1449 metering rod in and use the silver spring,did that still pings and dumps more black smoke.called back and got someone else and he told me i shouldnt have put those rods in because they are the richist ones for that carb.They dont know what to do ,how am i supposed to.The pistons are origonal pistons with cast iron rings.The gas i use is esso or shell which is best around here.
 
Do you know the history of the heads? If they were used, they could have been shaved and upped your compression. You could try some octane booster. We have a 340 6 pak and octane booster is a given.

With high compression, today's premium gas and having the timing off just a little it will ping.

Good luck.
 
If the compression is a true 10.5:1 you have too much cylinder pressure and you need a larger cam. Most "10.5:1"pistons in a 340 block end up around 9.4:1 depending on the machining. However, if it's puking smoke, you need to learn how to tune and then fix it. It's the cheapest way to get it to stop. Tech lines don't have the car sitting in front of them and you do. So i'd suggest you buy the strip kit for that carb, get a vacuum gage, a timing tape, and we can help you learn to do it.
 
Are you using vacumn advance?? Be sure to check your timing with the advance hooked up at whatever rpm you want all your advance in at. You will find it adds a lot of advance(timing to your total). You can change this inserting an allen wrench thru the canister hose nipple. If my memory serves me correct clockwise retards and counterclockwise advances.
If all else fails blend some 110 race fuel in it.
 
1st, back the total timing to 30* full advance.
and slow the advance rate down, get full advance by 3200 rpm or leave the rate as stock, you can still maintain a higher intial, but the adv rate will have to sllooooow down.
what gears?

Then lean the carburetor out, 100 jets primary/.095 secondary 70/47 rods orange springs-that how the 1405 is setup
try the second setting on pump arm too.

Black smoke-RICH

FWIW- every 1406 i've used on a cam'd 318-360 was LEAN.

Though right now you are too rich.
 
dart gt said:
compression is 10.5to1 and premium fuel.i tried step up springs,4 barrels open sharper but still pings and blows black smoke.called eddys teck line and they told me to put a 1449 metering rod in and use the silver spring,did that still pings and dumps more black smoke.called back and got someone else and he told me i shouldnt have put those rods in because they are the richist ones for that carb.They dont know what to do ,how am i supposed to.The pistons are origonal pistons with cast iron rings.The gas i use is esso or shell which is best around here.
Click to expand...

I agree you have WAY too much cyilinder pressure for that cam.
That's why I asked.

I think timing will help this like already mentioned yes, it is already way too rich if it's smoking like that.

If you follow the timing suggestiosn given to you and lean this thing out, I think you'll be ok.
 
thanks everyone for your help.Pushed distrubutor towards firewall just a bit and tried it.worked perfect.Put 800 termoquad on and tried it,workes good,no smoke or pinging.Just have to dial in carb.Any tricks to setting a thermoquad up to work good?
 
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