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283 Question

5K views 20 replies 7 participants last post by  GoneNova/406 
#1 ·
I have a 1963 Impala Convert with a 283 Rochester 2 Barrel Carb. How many CFM's is the stock rochester carb? If you do the math you come up with 409 CFM-----> (283 cu in X 5000 RPM max=1,415,00 / 3456 = 409 CFM)
I can find a 4 barrel Holley # 0-8007 with 390 CFM and a 2 barrel Holley 0-7448 with 350 CFM also might be able to use a Holley 2 barrel 0-4412c with 500 CFM My other question is what happens if I use the 500 cfm carb on my stock 283 ? Will it be over carb- ed and maybe bog or use to much gas.
I 'am not looking for more power just a better crusing carb for this car.
Thanks Dan
 
#10 ·
65 I believe.............That one in the picture is a later one....maybe 68-74, judging by the lack of oil fill hole and spring choke setup. It would work on your 283, but you would have to get valve covers with an oil fill access.
 
#13 ·
I would go with the edelbrock....if nothing more than, you can bolt either a spreadbore (Quadrajet) or squarebore (Holley, Carter, Edelbrock) to it........

The Quadrajet that you are looking for is a pre 75 (I think)....the serial # will start with 70...not 170.......The sreial # is stamped up the side of the back barrels on the drivers side of the carb.

Love the car BTW...I have a 62 Canadian Pontiac which is very similar.
 

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#17 ·
That intake should work for you.......

That carb is designed for the spring choke .........the spring goes in that pocket in the manifold. The electric choke carbs will bolt to your manifold with the proper gasket.
 
#19 ·
Yeah that's the one.............

I am no expert on Quads.......I think there are just 2 cfm ratings...725 and 800 on some big blocks....but don't let that get you down. Quads are a different type of carb......on a small engine, they will only flow what is needed.....If it needs 500 cfm, thats what you get. Maybe someone else on here can explain how they work better. When it comes to mileage, they are pretty hard to beat.
 
#20 ·
Found some info on Q-Jets they came in 486 cfm, 553 cfm, 600 cfm ,692 cfm,700 cfm, 750 cfm and 800 cfm. The primaries are rated at 160-225 cfm . I still need to find out how to tell what cfm's are on a Q-jet carb .

Decode your Q-jet

Produced 1976 or later
17080243
2629 CNO
170 - Prefix Code
8 - Decade Produced
5 - 1976-1979 (1705)
8 - 1980's (1708)
0 - Year Produced
2 - Model
0 - Monojet (1 bbl) Federal standards
1 - Two jet (2 bbl) Federal standards
2 - Quadrajet (4 bbl) Federal standards
3 - Monojet (1 bbl) California standards
4 - Two jet (2 bbl) California standards
5 - Quadrajet (4 bbl) California standards
6 - VariJet (2 bbl) Fed
4 - Division.
0, 1, and 2 all indicate Chevrolet.
4 - Buick
5 - Olds
6,7 - Pontiac
3 - Transmission
Even numbers - Automatic Transmission
Odd numbers - Manual Transmission
CNO - Customer Code
2629 - Date Code
262 - 262nd day of the year
9 - Year

Pre-76
7028219
DG 1938
70 - Prefix code. "70" will appear on all late '60's Rochester Carburetors.
2 - Decade produced.
2 - 1960's
3 - 1060's with A.I.R.
4 - 1970-1975
8 - Year produced. 8 = 1968
2 - Model
0 - Monojet (1 bbl) Federal standards
1 - Two jet (2 bbl) Federal standards
2 - Quadrajet (4 bbl) Federal standards
3 - Monojet (1 bbl) California standards
4 - Two jet (2 bbl) California standards
5 - Quadrajet (4 bbl) California standards
6 - VariJet (2 bbl) Fed
1 - Division.
0, 1, and 2 all indicate Chevrolet.
4 - Buick
5 - Olds
6,7 - Pontiac
9 - Transmission
Even numbers - Automatic Transmission
Odd numbers - Manual Transmission
DG - Customer code.
1938 - Date Code
193 - 193 rd Day of the year
8 - Year
 
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