Just about ready to pitch my Holley 4160

[Arl37]

305 1969 C10 stock except for headers
Added Edelbrock performer Manifold and a Holley 4160 I rebuilt
Stars fine. Idles fine.
Timing about 15 degrees
Floats set correctly.
Idle screws set correctly.
Acclerator cam is pink in #1 hole
Went fom 31 to 35 on acclerator Jet.
Pretty sure I have accelerator pump adjusted correctly
Still bogs off line but whe going is very strong
think I have read every article on Forum and U tube on adjusting Carb
Am I missing something?
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[geezer#99]

What do you have for an air cleaner?
Timing about 15*!! Do you have it set right?

[Arl37]

Just new cheapie Edelbrock air cleaner. What do you thingtiming ashould be?,
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[cpetersen]

Mine is going the other way. Mine runs really good with a 28 accel nozzles, but im still getting an occasional backfire through the carb. A guy at the local speed shop told me it was to lean. But if it boggs it is to big of a nozzle. I'm going to change the pump today, and change the nozzle back to the 28. mine is a 3310-1, I even blocked off the rear power valve. I'm getting pretty good at changing power valves. lol

[Arl37]

Ive been thinking of going to a 28. Dont know if it makes any diffrence but Iam at sea level in San Diego.
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[geezer#99]

Originally Posted by Arl37

Just new cheapie Edelbrock air cleaner. What do you thingtiming ashould be?,
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The reason I ask about the cleaner is cause if the top lid is too close to the air vent on the top of the carb it causes a bog sometimes. Screws up the vacuum signal to the carb. Try it without the cleaner on.
Timing should be 12-14*. If it's set right. Have you verified tdc on #1 lines up the timing mark at 0* on the tab. Vacuum plugged to dizzy while setting timing. Some 305's had different timing marks on them.

[sbc10guy]

I have a holley 650 carb with the same problem and i have 28 front and 29 rear, i am interested to find out what fixes it.

[Arl37]

Gezzer. I will double check tdc on #1 today.
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[cpetersen]

I always thought that you need to lean it at sea level. If you were in Denver you would have to fattin up. I know the fueller guys have alot of problem in Denver and run such fast times in houston.

[prostreetC-10]

Originally Posted by cpetersen

I always thought that you need to lean it at sea level. If you were in Denver you would have to fattin up. I know the fueller guys have alot of problem in Denver and run such fast times in houston.

Absolute exact opposite. More air at sea level so you have to fatten and vise versa at altitude. Now let's just put the brakes on here for a minute. First of all, Holley jets all of their carbs for sea level. They tend to be just a TAD rich out of the box to protect your motor.

You say it's a 4160 which covers about 100 carbs it could be. Please give the specific "list" number. We have to get this out of our heads guys that if there is a "hesitation" that we MUST raise the shooter size to the moon!! Holley does a very good job of putting the correct shooter size on their carbs. Yes, it can sometimes help but there was NEVER a 4160 carb that came factory with a 35 shooter and that is way too big. Need to verify your timing IS correct. Also need to make sure you have the correct jetting and power valve installed.

Need to verify you also have the correct carb on your motor. Please give us some more info on the carb and the motor. Once you have given the list number, provide the numbers that are stamped on the top or the side of the metering block(s).

[Arl37]

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[Arl37]

Thanks for Jumping in Prostreet
Engine is 1972 C10 305. Unmiodified except headers and the 4 barrell I just installed on Edelbroick performer.
Time is 12 degrees BTDC
Doubled checked dist install. Runs smooth idles fine plenty of power. just bog on take off
Carb it LiSt-9834-1
1159
Metering block on front( at least i think it is mettering block) is 10959. Dont see anything
on rear of carb

Front metering block is 10959
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[davepl]

When you say off the line, do you mean on a hard launch? If sufficiently hard you can get fuel slosh out of then vent tube and down into the carb, causing a rich-bog. Racers often connect the two vents together with a loop of hose and a vent on top of that. You could just try sticking a length of hose on the vents to raise their top a couple of inches as a temporary test.

Like I said, though, that's only on a launch sufficiently hard to cause fuel slosh.

Have someone watch you do it to see if there's black (rich) or white (lean) smoke out the exhaust, that'll at least tell you which direction you need to go.

[Arl37]

I will check tha that davepl.
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[prostreetC-10]

This is a 600 vac carb on a 305 in a truck. I'm pretty sure he is not launching too hard! lol

Actually the 9834 is not a very common 600. When you say "bog" do you mean "hesitation". A bog is usually used to describe too much fuel and a hesitation is a lean condition.

I'm not too well versed on the 305 but most motors can take a decent amount more initial timing.

[Arl37]

Prostreet. It is a hesitaion.
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[davepl]

It's a longshot but make sure your vacuum advance is hooked up to the proper timed port. If you had it on manifold vacuum, and then set the timing that way, all that advance would "go away" when you got into the throttle.

As to which port is the timed port, you'll need a manual or a Holley expert. But generally there is -not- vacuum present at idle, or very little. If there's full vacuum at idle, it's not the timed port.

[shocker]

tough to say without being there but i would be reducing fuel on accelerator pump. if you were to lean it should backfire through the carb on hard acceleration. 305s cant swallow alot of fuel without some gear or converter

[BOZO]

Check the PCV valve also. I recently bought a new aftermarket carb to replace the stock one and still had my hesitation until I changed out the PCV valve which I thought was good. Spent $250 when $2.50 would have fixed it.
And make sure the vacuum advance diaphram and the brake booster diaphram(if you have one) doesn't leak.

[rsavage]

How tired is the 305? Timing chain stretched some? 600 cfm seems like a pretty big gulp for a stock 305 .If it was too lean wouldn't it be backfiring through the carb? I'm no Holley expert.

[Arl37]

Well, things are getting better. I did delay the aerator pump fuel shot by shorting the acclerator stroke. ( Shortned the screw spring thing) and now I am down to a much milder studder. Maybe I had it preloaded an giving it too much fuel. Im going to fiddle with some tomorow and see if I can improve it a little more.
On another note I had a senior moment when I said it was 305. IT IS ACTUALLY A 72 307!

Bozo. New dist. New Vaccum brake booster. New PVC Valve.

vacuum on timed port.
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[prostreetC-10]

Originally Posted by Arl37

Well, things are getting better. I did delay the aerator pump fuel shot by shorting the acclerator stroke. ( Shortned the screw spring thing) and now I am down to a much milder studder. Maybe I had it preloaded an giving it too much fuel. Im going to fiddle with some tomorow and see if I can improve it a little more.
On another note I had a senior moment when I said it was 305. IT IS ACTUALLY A 72 307!

Bozo. New dist. New Vaccum brake booster. New PVC Valve.

vacuum on timed port.
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The part in bold does not make any sense to me. You shortened the spring by tightening the 3/8th nut on top right? Didn't that create a bunch of slack? That actually doesn't shorting the stroke. The longer the spring is, the further into the stroke the arm is thus shortening it. That certainly shouldn't make a lean condition better. It should make it far worse because you are taking the needed fuel out that corrects the lean condition when the primaries are opened. The other problem with having the arm too far into the stroke at rest is that when you are at part throttle going down the road, you have almost no shot left to help the A/F ratio when you stab it or try to pass....something like that. Kinda scratching my head.

[Arl37]

What u say makes sense. Maybe by shorting it I am gvig it a bigger shot and tha tis wha t Ineeed?
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[prostreetC-10]

First we have to get back the the fact that the 35 shooter is WAY TOO big. There is a chance that taking some stroke out helped a tad but that really should only affect the duration of the shot and not the amount. You can't shorten the stroke and give it a bigger shot because you are actually preventing it from getting to the larger part of the pump cam. The pink cam is very progressive unlike and orange or white that has a quicker ramp. It gets a little complicated but the spring play a roll in keeping the shot going after the pump arm has stopped moving because it collapses some when the throttle is hit hard than then recoils to keep the shot going after the arm stops moving. If you shorten (collapse) the spring, you take away it's ability to keep the pump shot going.

[Arl37]

already replaced the 35 with the 31. So what color cam should I be using?
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