Carburetor question
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
There is very little difference between them. Jets and rods are likely different, and there may be some minor design differences for their respective applications. But you can rebuild the truck carb into a good performing carb that will function fine on your C3.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Rudy -
It depends on the year of the carb. Q-Jets in the years 1968-1974 had very little difference between the truck and car carbs. You can set up a truck carb to run as well as a car carb. Starting in 1975, the carbs changed. The truck carbs were given different booster venturies to improve fuel flow and throttle response in the very low rpm range (for lugging and towing). With the stronger metering signal from these boosters, the primary metering rods were also changed in their design: The truck metering rods have .036" diameter power tips to prevent the carb from going over-rich at WOT, whereas the car rods are .026. Installing the truck carb on a high-reving Vette engine proves a little difficult to tune in most cases, and I recommend avoiding these carbs for a Vette application. But the truck carbs do work very well on trucks...
Lars
It depends on the year of the carb. Q-Jets in the years 1968-1974 had very little difference between the truck and car carbs. You can set up a truck carb to run as well as a car carb. Starting in 1975, the carbs changed. The truck carbs were given different booster venturies to improve fuel flow and throttle response in the very low rpm range (for lugging and towing). With the stronger metering signal from these boosters, the primary metering rods were also changed in their design: The truck metering rods have .036" diameter power tips to prevent the carb from going over-rich at WOT, whereas the car rods are .026. Installing the truck carb on a high-reving Vette engine proves a little difficult to tune in most cases, and I recommend avoiding these carbs for a Vette application. But the truck carbs do work very well on trucks...
Lars
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Rudy,
Just for your future reference, I will always defer to Lars on the subject of Q-jet carbs....but thought I would let you know that most Q-jets of that vintage can be converted to most configurations required.
Just for your future reference, I will always defer to Lars on the subject of Q-jet carbs....but thought I would let you know that most Q-jets of that vintage can be converted to most configurations required.
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