quadrajet 455ho

gearhead63 · 08-23-2018, 10:55 AM

hi working on pontiac 455ho stock eliminator with a single booster quadrajet that runs fat in first gear from 5100 -5900 afr 11-11.5 anyone know how to fix this. regards magnus

Hacksaw · 08-23-2018, 04:55 PM

May be over rich with the secondary metering rods. The smaller the diameter of the rod the fatter you will be.

gsa612 · 08-23-2018, 07:35 PM

How is the carb set up,does it have primary rods and jets with the spring or just jets with no rods.Where's the float level?,fuel pressure?. gsa612

gsa612 · 08-23-2018, 07:55 PM

I just noticed it was a single booster carb.I believe it's only legal on a few cars yours being one of them.The guy you need is Danny Ashley,he's a member here,hopefully he'll see this.I don't have any current contact info,maybe someone here does. gsa612

ss3011 · 08-23-2018, 08:51 PM

There is a special system that the 1971 455 HO carb has , its called the POE system . Its purpose is to add extra fuel at WOT . You may want to get the Quadra Jet book by Cliff Ruggles , he has a section on that system . Most Q-Jets do not have that system , it doesn't meter fuel as well as having fuel go through the venturies . You say your engine only runs rich in 1st gear , are you running a Ram Air hood and air cleaner ? Which body style , GTO , Formula , or Trans Am ? Each has a different system .

Check Fig 11 https://www.gmcmi.com/wp-content/upl...ice-Manual.pdf

bob3240 · 08-23-2018, 10:14 PM

May be sloshing fuel out of the secondary metering rod holes. Do you have them sealed with tape or anything?

Todd Hoven · 08-24-2018, 08:53 AM

Quote:

Originally Posted by gsa612

I just noticed it was a single booster carb.I believe it's only legal on a few cars yours being one of them.The guy you need is Danny Ashley,he's a member here,hopefully he'll see this.I don't have any current contact info,maybe someone here does. gsa612

Danny is retired and living the quiet life, have to find somebody else.

rod butcher · 08-24-2018, 09:19 AM

Try Dean Oliver #870-830-5470

gearhead63 · 08-24-2018, 09:58 AM

the car is a 1972 lemans no ramair hood no aircleaner no primary rods just jets secondary metering rod holes are sealed float level 1/2 in fuelpressure 6psi accelerating well tubes are blockt afr 12.5-13.5 in second and third gear. regards magnus

FSA1673 · 08-24-2018, 11:44 AM

What size jet in the primary? Are you leaving off the two step, and does the condition get better with rpm? Sounds like it may be rich from being on the two step then clears up after.

08-23-2018, 10:55 AM	#1
gearhead63 Junior Member Join Date: Aug 2017 Location: sweden Posts: 16 Likes: 0 Liked 14 Times in 4 Posts	quadrajet 455ho hi working on pontiac 455ho stock eliminator with a single booster quadrajet that runs fat in first gear from 5100 -5900 afr 11-11.5 anyone know how to fix this. regards magnus

08-23-2018, 04:55 PM	#2
Hacksaw Senior Member Join Date: Sep 2016 Posts: 838 Likes: 148 Liked 276 Times in 151 Posts	Re: quadrajet 455ho May be over rich with the secondary metering rods. The smaller the diameter of the rod the fatter you will be.

08-23-2018, 07:35 PM	#3
gsa612 Senior Member Join Date: Jan 2008 Location: 100th Meridian Posts: 570 Likes: 116 Liked 280 Times in 139 Posts	Re: quadrajet 455ho How is the carb set up,does it have primary rods and jets with the spring or just jets with no rods.Where's the float level?,fuel pressure?. gsa612

08-23-2018, 07:55 PM	#4
gsa612 Senior Member Join Date: Jan 2008 Location: 100th Meridian Posts: 570 Likes: 116 Liked 280 Times in 139 Posts	Re: quadrajet 455ho I just noticed it was a single booster carb.I believe it's only legal on a few cars yours being one of them.The guy you need is Danny Ashley,he's a member here,hopefully he'll see this.I don't have any current contact info,maybe someone here does. gsa612

08-23-2018, 08:51 PM	#5
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 885 Likes: 63 Liked 221 Times in 102 Posts	Re: quadrajet 455ho There is a special system that the 1971 455 HO carb has , its called the POE system . Its purpose is to add extra fuel at WOT . You may want to get the Quadra Jet book by Cliff Ruggles , he has a section on that system . Most Q-Jets do not have that system , it doesn't meter fuel as well as having fuel go through the venturies . You say your engine only runs rich in 1st gear , are you running a Ram Air hood and air cleaner ? Which body style , GTO , Formula , or Trans Am ? Each has a different system . Check Fig 11 https://www.gmcmi.com/wp-content/upl...ice-Manual.pdf Last edited by ss3011; 08-23-2018 at 09:07 PM. Reason: Added Link

08-23-2018, 10:14 PM	#6
bob3240 Member Join Date: Jan 2009 Location: lebanon ohio Posts: 250 Likes: 3 Liked 14 Times in 4 Posts	Re: quadrajet 455ho May be sloshing fuel out of the secondary metering rod holes. Do you have them sealed with tape or anything?

08-24-2018, 09:19 AM	#8
rod butcher Member Join Date: Dec 2005 Posts: 248 Likes: 291 Liked 129 Times in 24 Posts	Re: quadrajet 455ho Try Dean Oliver #870-830-5470

08-24-2018, 09:58 AM	#9
gearhead63 Junior Member Join Date: Aug 2017 Location: sweden Posts: 16 Likes: 0 Liked 14 Times in 4 Posts	Re: quadrajet 455ho the car is a 1972 lemans no ramair hood no aircleaner no primary rods just jets secondary metering rod holes are sealed float level 1/2 in fuelpressure 6psi accelerating well tubes are blockt afr 12.5-13.5 in second and third gear. regards magnus

08-24-2018, 11:44 AM	#10
FSA1673 Junior Member Join Date: Jan 2010 Posts: 81 Likes: 0 Liked 12 Times in 6 Posts	Re: quadrajet 455ho What size jet in the primary? Are you leaving off the two step, and does the condition get better with rpm? Sounds like it may be rich from being on the two step then clears up after.