Holley carb list #
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
Measure throttle blade sizes, venturii diameters, booster type and you can get close. Post a photo of your carb for us. I always stamp list nuber back into throttle body for future refrence when whacking off choke tower.
Thread Starter
Le Mans Master
Joined: Jan 2006
Posts: 6,504
Likes: 139
From: Butler Pa
It's mechanical secondary and I'm 99% sure it's an 850 cfm. The chart I was looking at shows 3 diferent #'s for an 850 and the only differences stated between the 3 were the jet sizes. Are there other differences?
Racer
Joined: Feb 2009
Posts: 273
Likes: 11
From: Algona, WA
The list# was stamped on the Primary and Secondary metering plates, as well as the base plate. The 650,750,850 cfm carbs would have the same venturi size for both Primary, and Secondary main bodies. Does it have idle adj, screws on Pri. only? or all 4 corners? What squirters in both size and style? How big are the excelerater pumps? Power valve in the primary side only? Type of boosters will also lend a hand at Identifying your carb. A 850 CFM like a 4781 would have 1 3/4 Pri. and Sec. Throttle blades.
A 600, 700, and 800 CFM carb would have smaller Pri. and slightly larger Secondarys There are also dash 1 thru 6 variants and revision in Jetting, Air bleeds, emulsion tubes and power valves, combined with jetting that have improved the response of these carbs.
Good luck
...Oh the numbers on the metering plates do not always match the list numbers and somtimes will need to be cross referance for application.
Dave.
A 600, 700, and 800 CFM carb would have smaller Pri. and slightly larger Secondarys There are also dash 1 thru 6 variants and revision in Jetting, Air bleeds, emulsion tubes and power valves, combined with jetting that have improved the response of these carbs.
Good luck
...Oh the numbers on the metering plates do not always match the list numbers and somtimes will need to be cross referance for application. Dave.
Thread Starter
Le Mans Master
Joined: Jan 2006
Posts: 6,504
Likes: 139
From: Butler Pa
I can't look at it right now but I believe the primaries and secondaries are the same size.
It has 4 corner idle adjustment screws.
Don't know what squirters they are.
Primary accelerator pump is 30cc. Secondary is 50cc (I think).
It has 4 corner idle adjustment screws.
Don't know what squirters they are.
Primary accelerator pump is 30cc. Secondary is 50cc (I think).
