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-   -   What carb is this? (https://67-72chevytrucks.com/vboard/showthread.php?t=861701)

Kalums 11-23-2025 04:54 PM

What carb is this?
 
Ok... Here is one for you guys, Holley doesn't have much information on this carb, I just realized it was in a box under the cradle portion of the actual crate my engine came in ( still have the wood crate...probably bought separately and shipped together with the engine, I'm assuming. ( I'm a lazy bum, was going to use it for fire wood when camping) it has a list number of 80712, All I can find is it should be a 670cfm "from GM". It has vacuum secondaries and is a square bore. Literally nothing else. Any and all info would be appreciated.

70STOVEBOLT 11-23-2025 09:07 PM

Re: What carb is this?
 
A pic would be helpful

70STOVEBOLT 11-23-2025 09:10 PM

Re: What carb is this?
 
Here is a thread on the Holley forum that shows that number to be 670 CFM Syreet Avenger. YMMV

https://forums.holley.com/forum/carb...g-a-carburetor

Kalums 11-23-2025 09:35 PM

Re: What carb is this?
 
Quote:

Originally Posted by 70STOVEBOLT (Post 9412015)
Here is a thread on the Holley forum that shows that number to be 670 CFM Syreet Avenger. YMMV

https://forums.holley.com/forum/carb...g-a-carburetor

You rock! I wonder why my internet searches did not pull that up... *face palm * dang google overlords...
Do you think I would be better off with that than trying to find a 2 stage power valve for my 9895?

70STOVEBOLT 11-24-2025 10:41 AM

Re: What carb is this?
 
There are too many variables to say, but the 9895 is a 650 spreadbore and the 80712 is a 670 squarebore. With only 20 cfm difference, I would match it to the intake so you don't have to run an adapter.

Kalums 11-24-2025 11:07 AM

Re: What carb is this?
 
Quote:

Originally Posted by 70STOVEBOLT (Post 9412082)
There are too many variables to say, but the 9895 is a 650 spreadbore and the 80712 is a 670 squarebore. With only 20 cfm difference, I would match it to the intake so you don't have to run an adapter.

The intake is an Edelbrock 2104 intake, so... Bolt pattern isn't an issue, but I would probably use that metal "flange" gasket Holley mentions in the install instructions. Would I be better off with a 6210-3? Or a 3310? I've got both, they are both spreadbore but have mechanical secondaries... I'm just trying to figure out which would cause less hassle... Because I'm pretty sure my power valve is bad and the 9895 has a 2 stage which no one makes any more. I guess I'm looking for experience/advice as the truck runs fine 80% of the time but every few starts it idles rough and has a really weird "tip in" stumble... When you give it the juice, not even hard acceleration.

70STOVEBOLT 11-25-2025 09:25 AM

Re: What carb is this?
 
For a street application, it will be easier to live with the vacuum secondaries vs. mechanical. Better fuel mileage also, if that is even a concern. Tip in stumble a lot of times is attributed to the accelerator pump or a timing/vacuum issue. If it fine 80% of the time, it very well could be the power valve. Does it ever backfire when you get on it? A bad power valve can also cause backfiring. Do you have a fuel pressure regulator on the truck? With modern mechanical pumps, high fuel pressure is a common issue that could be causing the carb to flood, which could also cause a stumble.


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