Foxy Green Foxbody Build

89 Fox 427 said:
No, 24 base
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Is this the same carb as last year? If so did it act this way last year. I'm wondering about the adjustments you made the other day
As far as carb size my set up was 408 cubes, 268/276 dur @ .050, 636 lift, 12.8:1, 600hp/500lbs with a 850 holley aed
 
89 Fox 427 said:
The tip in is fucked off. I have to blip the throttle to take off with the clutch, if I ease into throttle it goes lean. I need to do a search for vacuum leaks or something. The accelerator pump seems to be adjusted right at zero lash so I don't know what else would cause that stumble.

Anther symptom (maybe) is light throttle in cold start to try and keep it running and it leans out and dies. Maybe the carb is gummed up
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This carb have a functional choke?
 
89 Fox 427 said:
Let's have an actual discussion amongst members, I know a lot of you don't like to discuss stuff because "internet experts".

I know the gauge is just a guide, or reference, and helps paint a larger picture, but for piece of mind can I get your guys thoughts on AFR.

Id consider these "target" numbers if I had to paint the picture even though it's more dynamic than this:

13.5 cold idle/ warm up
14.5 normal idle
14.5 light cruising
13.0 moderate acceleration
12.0 WOT
17.0 deceleration

Ready, go
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If the cam has a bit of overlap I'd have the "normal" idle a little richer, somewhere around 13.5 and probably be slightly leaner at WOT ~12.5 as a starting point and tweak it from there.

Have you tried squaring the primaries? Square the primaries, set the idle a little richer and I think you'll get a big improvement in drivability. With the primaries somewhat closed and the transfer slot covered you're relying on your already slightly lean (IMHO) idle port to supply fuel on the initial opening of the throttle before it exposes the transfer slot. Of course this is all theory/my opinion (happy to be proved wrong) but there is no risk in trying it.

If you're not already, get yourself a writing pad or something similar and write down every change you make (making them one at a time after your initial set up) and document what effect the change had. You'll learn more this way than anyone here can likely teach you.
 
No choke.

We're not dealing with a carb problem.

Yet.

I appreciate the responses so far but after what I discovered today timing is my number one problem. It's all over the place. My distributor is being disassembled and evaluated.

Vac advance plugged off today to get a baseline. If I set base at 16 sometimes it shows 20, sometimes 18, sometimes 16. Its not the timing light, because my idle is also all over the place anywhere from unstartable (400rpm) to hanging at 1200+. Because timing is erratic. With transfer slots squared it idles wayyyy to high. I have to close the secondaries all the way, and close the Primaries quite a bit to get rpm to drop to 750/800.

Today's little test was to start the car, set timing at 16 base. Hook up vacuum adv to manifold (timed) and see what it does. We'll I hook up the vac, and it would only raise timing 2 degrees. So I blip the throttle, then it should show 28 to 30 degrees and hold steady there at idle. Unplug vacuum advance it would drop back to 16. Plug it back in, only go up 2 degrees, blip the throttle, back to 28 degrees. Something is sticking. But even with the advance plugged my timing doesn't stay still. Cold is one number, hot is another. The gear looks fine.

Also today I'm only seeing 4" to 5" vacuum. I don't know where my vacuum went, but I would bet timing has something to do with it. I was previously seeing 10-12"

I'm chasing my tail.

Timing first. Carb later.
 
I agree, figure out timing first.

Really the only reason I asked about a choke, was because if you did have say a manual pull choke hooked up, you can utilize it to help diagnose some carb issues.
 
89 Fox 427 said:
No choke.

We're not dealing with a carb problem.

Yet.

I appreciate the responses so far but after what I discovered today timing is my number one problem. It's all over the place. My distributor is being disassembled and evaluated.

Vac advance plugged off today to get a baseline. If I set base at 16 sometimes it shows 20, sometimes 18, sometimes 16. Its not the timing light, because my idle is also all over the place anywhere from unstartable (400rpm) to hanging at 1200+. Because timing is erratic. With transfer slots squared it idles wayyyy to high. I have to close the secondaries all the way, and close the Primaries quite a bit to get rpm to drop to 750/800.

Today's little test was to start the car, set timing at 16 base. Hook up vacuum adv to manifold (timed) and see what it does. We'll I hook up the vac, and it would only raise timing 2 degrees. So I blip the throttle, then it should show 28 to 30 degrees and hold steady there at idle. Unplug vacuum advance it would drop back to 16. Plug it back in, only go up 2 degrees, blip the throttle, back to 28 degrees. Something is sticking. But even with the advance plugged my timing doesn't stay still. Cold is one number, hot is another. The gear looks fine.

Also today I'm only seeing 4" to 5" vacuum. I don't know where my vacuum went, but I would bet timing has something to do with it. I was previously seeing 10-12"

I'm chasing my tail.

Timing first. Carb later.
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Always gotta be 2 or 3 things wrong at the same time, just to make you wonder why you do this, lol.
I will say this, the more problems you have the more you learn, imho.
I agree on timing 1st carb later. When I said the carb will cause issues ahead of timing that was assuming you had a decently timed engine and properly functioning distributor.
 
If you thought I'd be doing burnouts... me too. But instead I'm doing this

 
The vac advance doesn't do fuck all until at least 10" vacuum.. which for some reason I no longer have.

I can't rule out a vacuum leak though the tests haven't shown one yet
 
89 Fox 427 said:
The tip in is fucked off. I have to blip the throttle to take off with the clutch, if I ease into throttle it goes lean. I need to do a search for vacuum leaks or something. The accelerator pump seems to be adjusted right at zero lash so I don't know what else would cause that stumble.

Anther symptom (maybe) is light throttle in cold start to try and keep it running and it leans out and dies. Maybe the carb is gummed up
Click to expand...
Do you know about the idle transfer slots?
 
440roadrunner said:
Do you know about the idle transfer slots?
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The muffin man?

Yes I know the muffin man.

The transfer slot situation is another story. If I square them the car idles in outer space. Closing the secondaries is still too much rpm. Again, timing and vacuum are my priority because that may be most of the shit issues I'm chasing
 
I'm finding it hard to believe what I'm seeing as well. I need to get new vac lines, get rid of the plastic "T" in favor of a brass one or something. Maybe my vacuum was always low and the gauge in my car was wrong. The recent readings were a Bosch gauge 6 inches from the carb hooked to manifold vac on carb.

Im also questioning my timing light but they don't rent them here
 
Any opinions on switching from heat range 5 to heat range 7. Not trying to get ahead of myself, but I just bought 16 plugs of ngk bkr5e and thinking I should return them because... internet
 
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