help setting up carb....???

[originalnitro]

My 302 is also bored .030 over but my timing is at 14 degrees now but I was gonna try advancing it a little. If that doesn't work then I'll try ur setup....would it help me at all to change cam positions now?

And on top of that the holley street avenger carb is dry flow tested whereas most carbs are wet flow tested to get their cfm so the holley street avenger 670 is really only a 600cfm

Go ahead and change the accelerator pump cam to hole 2 (if its the pink cam there are 3 hole in it might want to try it also lineup hole 3 on cam with 2 on carb) the 670 is closer to a 650 secondary butterflies are larger than the primaries. 302 bored .030 = 306

 

[ford1386]

Ok I'm gonna try it tonight and see how I make out

 

[ford1386]

didnt get a chance to try it yet hopefully tomorrow night

 

[ford1386]

I set timing to 17 degrees and hesitation is still there. And I tried using a different cam position on the accelerator pump lever but I have the orange cam with two positions. The carb plate has 2 holes, but I cannot line cam hole 2 up with hole 1 on the carb it is already on the ramp up part of the cam and pushes down on the accelerator pump lever so I may need a different cam...

 

[ford1386]

Bump............

 

[originalnitro]

Match hole 2 on cam with 2 on carb.

 

[kimcrwbr1]

Have you tried adjusting the idle screws to the rich side. At an idle turn the idle screws out for the highest rpm or vacuum then turn the idle stop to the idle speed you want. Then check them to see they are within 1/2 turn between them counting turns in then back out. try that then play with the accelerator pump.

 

[kimcrwbr1]

The idle jets still work at higher rpm and supplement the main jets also work your way up idle, accelerator,high speed

 

[ford1386]

Match hole 2 on cam with 2 on carb.

The carb has 2 holes and so does the cam, right now hole 1 on cam is lined up with hole 1 on carb, so therefore hole 2 is lined up with hole 2. But does the pink cam have three holes?

 

[originalnitro]

The carb has 2 holes and so does the cam, right now hole 1 on cam is lined up with hole 1 on carb, so therefore hole 2 is lined up with hole 2. But does the pink cam have three holes?

with the screw in 1 # 2 should not be lined up will be close. Holes #1 and 2 deliver the about the same amount of fuel but 2 delivers more sooner.

 

[originalnitro]

Also what discharge nozzle are you useing? The smaller ones cant flow the fuel fast enough.

 

[ford1386]

The factory holley nozzle I think it is a 28

 

[originalnitro]

Step up to a 35

 

[baddad457]

A small carb is ALWAYS easier to set up than a big one. The fuel metering signal is much stronger on a small carb.

At 5,500rpm and 100% volumetric efficiency a 480cfm carb would be perfect. You don't have 100% ve. After all of those turns and bumps and valves closing a surging the air back and forth you would be lucky to see 80% on a good set of heads at the rpms we really run. A 390cfm would be great on that. A 500cfm AFB would be perfect.

So why is your carb not working well? It's too damn big. Try to blow through a 2' section of 3" pipe and see if you can feel the air on the other end of it. The carb needs to feel ther air. It draws off of air moving through. A carb doesn't force anything--the engine does the work. Does a little 302 move enough air to create a reliable signal in a 670cfm carb?

No.

I'm sure it could be crutched to run okay, but it will never have crisp response and you will not need the secondaries. You need a carb with will have the throttle plates standing wide open at full power. Forget all the homerisms about carbs. You have to drive this on the street. I would find something around 400cfms.

I could get that running, what you have, but it won't run as well as the right carb would.

His carb, while it is a tad on the large size, is definately not too big. I've run a vacuum sec 3310 750 on a 302 and it was fine in all respects. Was the throttle response as good as the 570 that's on it now ? No. But it worked just fine. Did the secondaries open ? Yes. Just not all the way. His problem is most likely due to the accellerator pump linkage having too much slack in it. If not that, then the timing could be retarded too much.

 

[ford1386]

My timing is at 17 degrees how much more should I go