Need to ID a Qjet
Need to ID a Qjet
04-20-2006, 09:25 PM
#2
Gold Member
Re: Need to ID a Qjet
Hey Phil, this is what I got from all this.
7046222
704- It was used on 1970 to 1975 GM vehicles
6- 1976 production date
2- Its a quadrajet 4bbl federal standards
2- Chevrolet
2- automatic transmission.
Did this come off a car or a boat?
Heres the link I found.
http://www.carburetion.com/quadnumber.htm
John S.
7046222
704- It was used on 1970 to 1975 GM vehicles
6- 1976 production date
2- Its a quadrajet 4bbl federal standards
2- Chevrolet
2- automatic transmission.
Did this come off a car or a boat?
Heres the link I found.
http://www.carburetion.com/quadnumber.htm
John S.
04-22-2006, 12:33 PM
#3
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Thread Starter
Re: Need to ID a Qjet
Yes it is a Volvo carb I picked up a long time ago and forgot what it cam off of, trying to find the CFM. I am running a DP 750 Holley now but would like smaller Primary barrels for obvious reasons but still be able to open the man hole covers for WOT. I have had a few Qjets and I like them a lot more then the Holley's.
Phil
Phil
04-23-2006, 01:02 PM
#4
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Re: Need to ID a Qjet
Quadrajets are 750 cfm carbs with the exception of an 800 cfm version that came on some big Caddys, and Buicks (maybe others). If it's an original marine carb, the casting number decode might not mean much. I have the original Q-jet on my 1988 OMC. The casting number decodes to a mid 80's Chevy with an auto, but the OMC manual shows my casting number as the original carb. I was also able to get the correct marine rebuild kit based on that number. It all depends where you look. Also, the bowl vent on some of these carbs (like mine) is not a "J" tube. Instead, the casting around the tube is made in such a way that a dam is formed causing any overflow from the tube to flow only into the carb throat, and not to the outside. If you compare it side by side to an automotive carb, you'll see the difference.
I've only seen this casting difference twice, and both times it was on an original marine Q-jet (80's vintage).
These carbs are a little more complex to set up than a Holley. But done right, they work well.
I've only seen this casting difference twice, and both times it was on an original marine Q-jet (80's vintage).
These carbs are a little more complex to set up than a Holley. But done right, they work well.
04-23-2006, 01:12 PM
#5
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Re: Need to ID a Qjet
I forgot to add a simple way to determine if you have a 750 or 800 cfm carb is to measure the primary venturies.
1.09375" (1 3/32") = 750cfm
1.21875" (1 7/32") = 800cfm
This is venturi size, not throttle bore size.
Paul
1.09375" (1 3/32") = 750cfm
1.21875" (1 7/32") = 800cfm
This is venturi size, not throttle bore size.
Paul
04-23-2006, 01:52 PM
#6
Re: Need to ID a Qjet
I agree with Liberator21 Rochester are very fine for stock application. Just make sure you are jetted to your application.
Most Small block and Big block uses the same 750 CFM but are different in jets and Secundary metering rods. I one carb for 350 260 hp and one for 454 330. I can find out the numbers of the jets and secundary meterings rods if you are interested?
Most Small block and Big block uses the same 750 CFM but are different in jets and Secundary metering rods. I one carb for 350 260 hp and one for 454 330. I can find out the numbers of the jets and secundary meterings rods if you are interested?
