400 Backfires through carb
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New User
Joined: Jun 2011
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From: Westminster
400 Backfires through carb
i recently put an edelbrock cam, new timing chain, water pump, mallory unilite distributor, edelbrock performer manifold and edelbrock 600 cfm carb on my 400. i got it started but it idles rough and when i try n rev it up fast it backfires through the carb. if i rev it slow it will rev up well and then it cleans up and runs strong at 1500+ rpm. any help on this matter would be appreciated.
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Check your distributor/timing (TDC) until someone more qualified answers. I'm in a similar boat but mine's not starting. I think mine made it back in wrong (I wasn't home at the time) and I think I'm hitting the wrong stroke, but I had to stop because it was getting dark and skeeters suck.
Mine backfired a little, then I adjusted it about 30 degrees, then it backfired a lot. Last try I just get clicking from the starter. I was jumping it from my car the whole time, so maybe the battery was just too dead, dunno(shouldn't be). Now it's charging, will have to see in the AM.
Mine backfired a little, then I adjusted it about 30 degrees, then it backfired a lot. Last try I just get clicking from the starter. I was jumping it from my car the whole time, so maybe the battery was just too dead, dunno(shouldn't be). Now it's charging, will have to see in the AM.
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Mine was off by 180*. After I fixed it, I had the same problem, so I rotated it about 10-20* to the left (toward the passenger side) and it stopped backfiring when I gave it gas. Obviously I still need to time it, but it will get you closer. I have the same engine so this should work.
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From: Westminster
*******
ok so i had a haynes manual for the pickup and of course i went off of the edelbrock installation guide that came with my cam to put in the plugs. wouldnt you know it the firing order on the edelbrock manual diagram showed 1-5-4-2-6-3-7-8 being the first motor i tore into i belived that because i knew nothing else. turns out the actual firing order is 1-3-7-2-6-5-4-8. holy **** i am stupid.....purrs like a lion now.... a little hesitation on acceleration which i believe i need to change the jets and metering in the carb because i live in denver any more thoughts?
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1-5-4-2-6-3-7-8 is on the 255, 302, 360, 390, and 460.
351 and 400 are different
I had a disagreement about how the cylinders are numbered 1234 on the pass side and 5678 on the driver's side, as opposed to 1357 and 2468. You could call em green, sunshine, fortune cookie, and taco as long as the firing order is right.
351 and 400 are different
I had a disagreement about how the cylinders are numbered 1234 on the pass side and 5678 on the driver's side, as opposed to 1357 and 2468. You could call em green, sunshine, fortune cookie, and taco as long as the firing order is right.
Fleet Mechanic
Joined: Aug 2010
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From: Cranbrook, Ont., Canada
I feel your pain. It took me awhile to figure that one myself. I figured that ALL fords had the same firing order, DUH. Then I went and asked a FORD mechanic and he set me straight. Now I know better. John
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