Originally Posted By MarkM
Originally Posted By Frankenduster
I agree but how far off does it have to be to be THIS bad?
A loss at high rpm would mean the cam would have to be WAAAAY advanced, right?

I had a 318 in a 74 Duster that was an absolute PIG out of the hole. It would not even peel out on gravel. It ran smooth as glass, quiet and nice. I swapped distributors, carburetors, spark boxes, I cranked the static timing to the moon...nothing made any difference worth mentioning. I pulled the timing cover to see that the cam sprocket was 2 teeth off the mark retarded ! I replaced the set since the chain had slop. Once back together, it would peel out easily on pavement and ran just as smooth as before.


I was just stirring the pot.

You said in your original post that the AFR goes lean the closer it gets 4k, but the fuel pressure remains steady all the way through. I'm going to say carb and not just because it's almost the only thing left at this point. lol. It really does sound like fuel starvation. If it were spark it wouldn't go lean and right up where it noses over it would get real choppy like hitting a rev limiter.



Ignition misfires certainly cause lean AFR readings. The cylinders pump pure oxygen ["air"] across the wideband, it's an oxygen sensor, not a fuel sensor.

We'll see here soon, there are only so many things that can cause it. Coil is next, it's newer, but a weak spark could be dropping out, I suppose.

From there I'll rob the rebuilt 600 AFB from the Dart and stick it on there.

After that, I'll find some Tannerite. ozbbq

1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
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