427 down on power

[patrickt]

FB -- How much throttle pedal travel do you have from when your foot is just touching the pedal to when you have it pushed all the way to the floor (in inches)?

[jhv48]

I bet it's a timing issue.

Check your initial setting first.

Then check to see if you are getting full advance at WOT.

[FatBoy]

Originally Posted by jhv48

I bet it's a timing issue.

Check your initial setting first.

Then check to see if you are getting full advance at WOT.

I've checked the timing and the advance and both are as they should be.
Resetting the float levels hasn't fixed it either.
I'm running out of things to check. I've just changed the spring in the vacuum secondaries for a lighter one, but I don't really expect that to make big difference.

Paul

[Ron61]

Paul,

Does the engine pull well up to 3,000 and then just flatten out and start to miss, or is it sluggish getting up to 3,000 under load? Also when you are just running it under no load. does it act the same way? That # 3 plug really looks as if it isn't firing at all and if they just ran the engine to break in the cam and not under any load, then it must have came from them the way it is unless you have added or changed something. I believe in an earlier post someone asked you if you had checked the valve springs as some engine builders use a light set to do the break in run with and then put the heavy ones in for the dyno and testing.

Ron

[FatBoy]

Hi Ron,
It isn't right all the way from tickover, but it really runs out above 3,000rpm.
Paul

[jhv48]

Is the sound the same from both of your exhaust pipes?

Or is one more muffled than the other?

[Ron61]

I don't think this would really prove much, but if you disconnect both exhaust pipes and just run it through the headers, (VERY LOUD ) does that make any difference? I think you are going to wind up having to do that anyway as that # 3 plug and the symptoms you describe sound as if the engine may have to come out. My 69 Cobra with the 428SCJ that is bored .065 over and blueprinted doesn't even run well until it is over 3500 RPM. The peak power is at 6300. And I had a smaller cam put in to lower that.

Ron