Primary Jet & metering rod info
11-04-2023, 06:10 PM
#1
Primary Jet & metering rod info
I'm new to this forum and I'm trying to determine the correct primary jet / metering rod for 1986 305 cu. in. LG4 with 5 speed manual. The carb that is on the car is a rebuild from NAPA. 17085204 which I believe was intended for a car with automatic transmission.
Can anyone tell me what Carburetor number would have been original and what jet / metering rod combo should be there from the factory.
Thank you so much.
Can anyone tell me what Carburetor number would have been original and what jet / metering rod combo should be there from the factory.
Thank you so much.
11-05-2023, 02:39 PM
#2
Re: Primary Jet & metering rod info
The carb you currently have is for a 1985 LG4 automatic. The correct number for 1986 LG4 manual is 17086005.
That being said, the calibration on closed-loop ECM controlled QuadraJets is much more the same across different
model years and engine/transmission combos than open-loop vacuum controlled versions. 1981-88 closed-loop
LG4 engines use 76 primary jets and 57U rods with a M hanger and CH rods for the secondaries.
The difference in the carbs between manual and automatic is in the base plate and choke assembly. The base plate
on manual trans carbs lack the tang for auto trans kickdown/TV cables and the choke has a 2-step cam vs.
a 3-step cam on autos.
That being said, the calibration on closed-loop ECM controlled QuadraJets is much more the same across different
model years and engine/transmission combos than open-loop vacuum controlled versions. 1981-88 closed-loop
LG4 engines use 76 primary jets and 57U rods with a M hanger and CH rods for the secondaries.
The difference in the carbs between manual and automatic is in the base plate and choke assembly. The base plate
on manual trans carbs lack the tang for auto trans kickdown/TV cables and the choke has a 2-step cam vs.
a 3-step cam on autos.
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