76 ford wide open problem
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76 ford wide open problem
I know I should be posting this in the 460 section, but no one goes on that much so forgive me
I have a 76 f250 460
10.1 pistons
Dove heads ported and dual valve spring
292 cam 513 lift
Advanced cam timing
750 vac sec Holley with airgap dual plane Intakw
I got the truck very crisp and clean on the lower Rpms with the carb. But when i hit it wide open, the exhaust gets raspy and sounds ritch, it pulls but not as hard as I think it should. Maybe it's because it's a 6,000lb truck on 39s and not a race car or do you guys think the secondary's are to rich? The secondary's are opening with the yellow spring. Thanks in advance
I have a 76 f250 460
10.1 pistons
Dove heads ported and dual valve spring
292 cam 513 lift
Advanced cam timing
750 vac sec Holley with airgap dual plane Intakw
I got the truck very crisp and clean on the lower Rpms with the carb. But when i hit it wide open, the exhaust gets raspy and sounds ritch, it pulls but not as hard as I think it should. Maybe it's because it's a 6,000lb truck on 39s and not a race car or do you guys think the secondary's are to rich? The secondary's are opening with the yellow spring. Thanks in advance
Lead Driver
Joined: Jul 2011
Posts: 8,679
Likes: 191
From: On the Edge of the Desert
There's no way for us to tell you that with what you've told us....
What jets are in it? What power valve? What vacuum spring? Do you have headers? Exhaust? What air filter do you have? Do you Have an air filter at all? Is it plugged up? What do the tail pipes look like? What do the spark plugs look like? Tuning using A wideband O2 sensor is the only way to be certain.
An F250 on 39" tires weighs a lot. What gears are in it? What transmission is it? Do you have a clutch fan? What color is the glove box door?
Exhaust note changing is typical, and nothing to be concerned with. I don't know what a rich exhaust sounds like. I don't think a hound dog could tell the difference in sound either. You don't tune your carb by what your exhaust "sounds" like. However you can tune it by what it SMELLS like. Although it's hard to sniff the tailpipe(s) when your driving down the road...
What jets are in it? What power valve? What vacuum spring? Do you have headers? Exhaust? What air filter do you have? Do you Have an air filter at all? Is it plugged up? What do the tail pipes look like? What do the spark plugs look like? Tuning using A wideband O2 sensor is the only way to be certain.
An F250 on 39" tires weighs a lot. What gears are in it? What transmission is it? Do you have a clutch fan? What color is the glove box door?
Exhaust note changing is typical, and nothing to be concerned with. I don't know what a rich exhaust sounds like. I don't think a hound dog could tell the difference in sound either. You don't tune your carb by what your exhaust "sounds" like. However you can tune it by what it SMELLS like. Although it's hard to sniff the tailpipe(s) when your driving down the road...
Thread Starter
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Senior User
Joined: Jul 2014
Posts: 246
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There's no way for us to tell you that with what you've told us....
What jets are in it? What power valve? What vacuum spring? Do you have headers? Exhaust? What air filter do you have? Do you Have an air filter at all? Is it plugged up? What do the tail pipes look like? What do the spark plugs look like? Tuning using A wideband O2 sensor is the only way to be certain.
An F250 on 39" tires weighs a lot. What gears are in it? What transmission is it? Do you have a clutch fan? What color is the glove box door?
Exhaust note changing is typical, and nothing to be concerned with. I don't know what a rich exhaust sounds like. I don't think a hound dog could tell the difference in sound either. You don't tune your carb by what your exhaust "sounds" like. However you can tune it by what it SMELLS like. Although it's hard to sniff the tailpipe(s) when your driving down the road...
What jets are in it? What power valve? What vacuum spring? Do you have headers? Exhaust? What air filter do you have? Do you Have an air filter at all? Is it plugged up? What do the tail pipes look like? What do the spark plugs look like? Tuning using A wideband O2 sensor is the only way to be certain.
An F250 on 39" tires weighs a lot. What gears are in it? What transmission is it? Do you have a clutch fan? What color is the glove box door?
Exhaust note changing is typical, and nothing to be concerned with. I don't know what a rich exhaust sounds like. I don't think a hound dog could tell the difference in sound either. You don't tune your carb by what your exhaust "sounds" like. However you can tune it by what it SMELLS like. Although it's hard to sniff the tailpipe(s) when your driving down the road...
Lead Driver
Joined: Jul 2011
Posts: 8,679
Likes: 191
From: On the Edge of the Desert
Black smoke is a sure indication of rich. So I would agree with you there. Possibly your secondaries are opening too soon?
Whatever the secondary jets are, I think it's safe to say they need to be smaller. By several steps. Figure out what they are or else were just gonna be shooting in the dark.
I've still never heard a rich exhaust. The "load up" sound is higher cylinder pressures and more powerful explosions. As well as the camshaft hitting its power band. Ever heard a Honda with V-tech?
Glove box door color... I have know idea HAHA
Whatever the secondary jets are, I think it's safe to say they need to be smaller. By several steps. Figure out what they are or else were just gonna be shooting in the dark.
I've still never heard a rich exhaust. The "load up" sound is higher cylinder pressures and more powerful explosions. As well as the camshaft hitting its power band. Ever heard a Honda with V-tech?
Glove box door color... I have know idea HAHA
Lead Driver
Joined: Jul 2011
Posts: 8,679
Likes: 191
From: On the Edge of the Desert
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FTE Emeritus
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From: springfield Missouri area
Wouldn't the carb he has have a metering plate instead of jets? If he has a 3310 it has a metering plate part number of 134-21.
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Lead Driver
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From: On the Edge of the Desert
Originally Posted by moose4x4
Wouldn't the carb he has have a metering plate instead of jets? If he has a 3310 it has a metering plate part number of 134-21.
Either way, he needs to cut fuel in the secondaries, whatever that takes.
Postmaster
Joined: Mar 2011
Posts: 2,698
Likes: 7
From: Taxachusetts
The yellow spring on the vac. secondary is too light causing your secondaries to open too soon. Go with a brown or black spring and let us know the results.
And keep the sunroof closed while you're testing this....the difference in air velocity and pressure over the sunroof to air in cab ratio is too great..... will cause the vehicle to wanna lift, thus resulting in a slower speed.
And keep the sunroof closed while you're testing this....the difference in air velocity and pressure over the sunroof to air in cab ratio is too great..... will cause the vehicle to wanna lift, thus resulting in a slower speed.
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