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#1
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I Got problem with the Carb Back Firing When Driving on my 273!!
OK,this is what i have a stock 273 with a 904 an a 8 1/4 with 3.21 posi, this is what i just did to it...swap the cam for a mopar performance with a duration of 260/268, Lift 430/450...and put a edelbrock performer with a Road Demon Jr. 525 cfm carb up top.....I left the stock ignition besides accel wires for now and timing is 10 degrees advanced....so it runs real smooth no problems at all but when i take it out for a drive ill give it gas an then it bogs down or back fires threw the carb....but when i give it more gas it stops doing it then it drives fine until iam below a certian rpm then it will do it again...i dont have a clue what it is, iam thinkn the demon carb or maybe i just need to upgrade to eletronic ignition??idk someone let me know.....
Today iam going to Change the plugs and see what that does..... |
#2
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hello, any time you put a bigger cam in a motor, the dist has to be recurved with a faster advance. then set timing at total at the rpm needed. what you have is lack of proper timing. just food for thought.
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#3
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sounds like your secondaries are closing to far and need adjusting .
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#4
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Spitting back thru the carb ususally indicates lean so make sure your accelerator pump is giving a good shot right from the gitgo. It won't pick up r's from low speed without it.
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#5
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I agree with this to a point. You must have your advance curve close(at best). Get your hands on an advance timing light(it will allow you to see where your at by the gun,instead of trying to see the marks on the dampner and you can turn the dial up and down-a big help) and set your total advance on the gun at 30*(to start). Rev it up to 2000 to 2300 and see if your light is at the TDC mark. This you may know,just trying to help.
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#6
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Get a good timing light...........
Then find TDC and install timing tape. Make sure you have true top dead center and then run engine speed to 3000 rpm. Set timing at 35 - 36 degrees total and that sould solve the problem even with the stock ignition. Recurve the dist. should help even more.
Then............................. Have fun! |
#7
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is the carb new?
i agree on checking the pump shot/arm adjustment. |
#8
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I'm a super pro drag racer When you increase your lift you must set your timing back to compensate. with that lift about 31 to 34 degrees is suffient
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#9
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I have a 273 that did the same thing. Pulled the heavier spring off the stock distributor, jetted a little richer, and properly adjusted the accelerator pump(Holley 390cfm). Now the car pulls through the lights much quicker.
BTW my axle ratio, cam specs, etc. are almost identical to yours. |
#10
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Quote:
I agree with Shaun and Tarrbabe. It is likely ignition/timing related. Start by following the above advice! |
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