Long Story Short On the Carb
02-27-2003, 11:53 AM
#1
Racer
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Long Story Short On the Carb
The rebuilt I bought from Zip 3 mos back ended up having a bent air horn so I'm replacing it with the edelbrock #1901 for my BB.. the question I have is.
The jets and rods in the edelbrock don't match the engine for my year for example. 71 had .077 jets and and the edelbrock has .069 . should I change all this first or put the carb on as is.. (i'm still learning) without changes and try it first. Remember I am also running a pretty hefty cam.. :confused:
The jets and rods in the edelbrock don't match the engine for my year for example. 71 had .077 jets and and the edelbrock has .069 . should I change all this first or put the carb on as is.. (i'm still learning) without changes and try it first. Remember I am also running a pretty hefty cam.. :confused:
02-27-2003, 12:42 PM
#2
Team Owner
I recommend putting it on as-is first, for one simple reason. Car should run fine, but if it doesnt, at least you won't be wondering if you screwed it up yourself when you took the top off and changed out the jets and rods! Secondly, you will have a baseline and will appreciate the performance gains you achieve when you make the changes. MJ
02-27-2003, 05:18 PM
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Re: Long Story Short On the Carb (71DropTop)
71 -
You can't directly compare one Q-Jet jetting combination to another: The Q-Jets had different internal fuel & air restrictor & bleed calibrations, and these changes cause the different Q-Jet model numbers to be jetted differently. For instance, BB cars did not have air bleed restrictors in the venturi area, whereas SB carbs did. This changes the jetting requirement.
One thing you will probably notice on your 1901 is that it is jetted a touch on the lean side: It has a jetting combination usually used on GMC trucks. With this in mind, and watching for lean indications, try the carb out and keep your jetting changes smart and conservative.
You can't directly compare one Q-Jet jetting combination to another: The Q-Jets had different internal fuel & air restrictor & bleed calibrations, and these changes cause the different Q-Jet model numbers to be jetted differently. For instance, BB cars did not have air bleed restrictors in the venturi area, whereas SB carbs did. This changes the jetting requirement.
One thing you will probably notice on your 1901 is that it is jetted a touch on the lean side: It has a jetting combination usually used on GMC trucks. With this in mind, and watching for lean indications, try the carb out and keep your jetting changes smart and conservative.
02-27-2003, 08:36 PM
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Racer
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Re: Long Story Short On the Carb (71DropTop)
OK the Edelbrock 1901 is in and this baby fired right up :cheers:
with the exception of a few minor adjustments I actually took it for a ride without even turning a screwdriver!!! :thumbs: :thumbs: not bad for out of the box :D and again leave it to the forum for great advise...... It is always appreciated. :cheers:
[Modified by 71DropTop, 8:38 PM 2/27/2003]
with the exception of a few minor adjustments I actually took it for a ride without even turning a screwdriver!!! :thumbs: :thumbs: not bad for out of the box :D and again leave it to the forum for great advise...... It is always appreciated. :cheers:
[Modified by 71DropTop, 8:38 PM 2/27/2003]
02-28-2003, 02:07 PM
#7
Melting Slicks
Re: Long Story Short On the Carb (71DropTop)
The 1904 I run is a bolt on out of the box deal too.The 406 has a fairly lumpy cam,and I find the idle is rich.I was told the power valve springs may be too strong for my cam,and at this stage I'm leaning towards a Holley 3310.
Just thaught you might need to switch springs before you start with the jets.
Just thaught you might need to switch springs before you start with the jets.