What CFM is this carb? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bsgmcc20 · 12-31-2008, 09:47 PM

I am looking all over the net for info. found its a 1970 Rochester quad but not what cfm it is.

numbers are below

7040206 1 F
22091

any help? 750 or 800?

This is off a Bone stock 396 three speed auto with a non posi

petey-pablo · 01-01-2009, 09:00 AM

I have No Idea but heres A bUMP--^

1968SWBBigBlock · 01-01-2009, 09:30 AM

I found a 7040200 that is correct for 1970 396-400-454 for passenger car, vette, camaro, nova, & monte
They do not list the CFM but normally the BBC units are the higher flowing units
I also found a 7044206 which works for a nova or vette in 74 with auto - that would be a smaller cfm card
You should be able to find a 4 diget date code stamped into the base of the carb on the throttle lever side near the back bolt hole

neonlarry · 01-01-2009, 11:48 AM

Do you have the carb? If so here is a pic of the difference:
http://dyeager535.topcities.com/qjetidentify.html

suville · 01-01-2009, 12:08 PM

Most Q-jets are 750 cfm some Buick and Cads ran 800 the link neon sent shows the difference

**Jokers69** · 01-01-2009, 07:44 PM

There is a decoder
Rochester Number decoding

Example: # 7028219
DG 1938

7028219
Prefix code. "70" will appear on all late '60's Rochester Carburetors.
76 and later will start with "170"
2 - Decade produced.
702 - 1960's
703 - 1060's with A.I.R.
704 - 1970-1975
1705 - 1976-1979
1708 - 1980's
7028219
Year produced.
8 = 1968
If the number was 7045219 then
5 = 1975
7028219 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
7028219 - Division.
0, 1, and 2 all indicate Chevrolet.
4 - Buick
5 - Olds
6,7 - Pontiac
7028219 - Transmission
Even numbers - Automatic Transmission
Odd numbers - Manual Transmission
DG Production Plant Code.
1938 Date Code
193 = 193 rd Day of the year
1938 8 = Year

bsgmcc20 · 01-01-2009, 10:36 PM

Thanks for all the input.

The "bump" is what i need to look for. The Holley i have on it is a 650 off my other 72 with a 400sb. I was doing research on the quad and wanting to rebuild it and keep it orginal as much as i could. The Molding was damaged so that is the only casuality as of yet.

My idea for paint is white top with British racing green bottom.

http://fyi.gmblogs.com/2007/04/from_...ve_1970_2.html Here is a GM photo of the color idea
The green for the bottom
http://www.teglerizer.com/mgcolors/ Dark British Racing green Paint code PPG 9767

neonlarry · 01-02-2009, 02:43 PM

If you are looking for one, I have had good luck finding them on older caddies at pic & pull. Also look for one with an electric choke. And I would plan on a rebuild including rebushing the throttle shaft (possibly even changing the throttle shaft depending on linkage setup).

ChevLoRay · 01-02-2009, 03:22 PM

Jokers69....what a nice thing to post. I had seen that info before, but my damaged brain didn't dig it out of the annals of time, where it was buried. So, it looks like a 1970 Chevy Q-Jet for an automatic, without saying which engine it was on.

12-31-2008, 09:47 PM	#1
bsgmcc20 Im afraid of purple hangers.. Join Date: Oct 2008 Location: Central Cal Posts: 108	What CFM is this carb? I am looking all over the net for info. found its a 1970 Rochester quad but not what cfm it is. numbers are below 7040206 1 F 22091 any help? 750 or 800? This is off a Bone stock 396 three speed auto with a non posi Last edited by bsgmcc20; 01-01-2009 at 12:37 AM.

01-01-2009, 09:00 AM	#2
petey-pablo "THE GREEN GOBLIN" Join Date: Mar 2008 Location: Fremont Ca. Posts: 1,025	Re: What CFM is this carb? I have No Idea but heres A bUMP--^ __________________ Petey-pablo "THE GREEN GOBLIN" 1972 Cheyenne 10 Short Fleet Side Front 2.5inch Spindles with 2inch Springs Rear 4inch drop Springs. 454BBC TH400,Posi 1971 Cheyenne 10 Long Fleet Side 454BBC TH350,Posi Sold Drive it like you stole it! Petey-pablo@sbcglobal.net

01-01-2009, 09:30 AM	#3
1968SWBBigBlock Active Member Join Date: Oct 2006 Location: Ohio Posts: 1,643	Re: What CFM is this carb? I found a 7040200 that is correct for 1970 396-400-454 for passenger car, vette, camaro, nova, & monte They do not list the CFM but normally the BBC units are the higher flowing units I also found a 7044206 which works for a nova or vette in 74 with auto - that would be a smaller cfm card You should be able to find a 4 diget date code stamped into the base of the carb on the throttle lever side near the back bolt hole __________________ 1968 SWB 454 + .040, 490HP x 540 FT pounds of Torque 10-1 Kb Forged pistons, recon rods w/ ARP wave loc bolts 781 heads Ported with 2.19/1.88 SSTvalves Lunati 60204 cam, Micro Trol lifters, Ported Edelbrock Performer Rpm manifold armor coated, Pertronix Triple Strike Ignition Holley 770 Street Avenger carb,Headers armor coated Built by Watson Ruppel Performance in Sarahsville Ohio. Hardshift Tranny Built Turbo 350,TSI 10" 3000 stall 12 Bolt Eaton Posi 4.10 Richmond Gears moser axles 18.5" x 31" Hoosier Pro Street Radials ET Classic 5 Wheels - polished Power Steering, Power Brakes,Disc Brakes,Tach & Gauge Dash, Tilt,Factory Air (gone) Custom Paint & Body Work Special thanks to my wife, my son and my money tree

01-01-2009, 11:48 AM	#4
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,746	Re: What CFM is this carb? Do you have the carb? If so here is a pic of the difference: http://dyeager535.topcities.com/qjetidentify.html __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

01-01-2009, 12:08 PM	#5
suville Registered User Join Date: Jun 2003 Location: Mtn. Home, Idaho Posts: 906	Re: What CFM is this carb? Most Q-jets are 750 cfm some Buick and Cads ran 800 the link neon sent shows the difference

01-01-2009, 07:44 PM	#6
Jokers69 Active Member Join Date: Aug 2008 Location: Washington Posts: 147	Re: What CFM is this carb? There is a decoder Rochester Number decoding Example: # 7028219 DG 1938 7028219 Prefix code. "70" will appear on all late '60's Rochester Carburetors. 76 and later will start with "170" 2 - Decade produced. 702 - 1960's 703 - 1060's with A.I.R. 704 - 1970-1975 1705 - 1976-1979 1708 - 1980's 7028219 Year produced. 8 = 1968 If the number was 7045219 then 5 = 1975 7028219 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 7028219 - Division. 0, 1, and 2 all indicate Chevrolet. 4 - Buick 5 - Olds 6,7 - Pontiac 7028219 - Transmission Even numbers - Automatic Transmission Odd numbers - Manual Transmission DG Production Plant Code. 1938 Date Code 193 = 193 rd Day of the year 1938 8 = Year

01-01-2009, 10:36 PM	#7
bsgmcc20 Im afraid of purple hangers.. Join Date: Oct 2008 Location: Central Cal Posts: 108	Re: What CFM is this carb? Thanks for all the input. The "bump" is what i need to look for. The Holley i have on it is a 650 off my other 72 with a 400sb. I was doing research on the quad and wanting to rebuild it and keep it orginal as much as i could. The Molding was damaged so that is the only casuality as of yet. My idea for paint is white top with British racing green bottom. http://fyi.gmblogs.com/2007/04/from_...ve_1970_2.html Here is a GM photo of the color idea The green for the bottom http://www.teglerizer.com/mgcolors/ Dark British Racing green Paint code PPG 9767 Last edited by bsgmcc20; 01-01-2009 at 10:42 PM.

01-02-2009, 02:43 PM	#8
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,746	Re: What CFM is this carb? If you are looking for one, I have had good luck finding them on older caddies at pic & pull. Also look for one with an electric choke. And I would plan on a rebuild including rebushing the throttle shaft (possibly even changing the throttle shaft depending on linkage setup). __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

01-02-2009, 03:22 PM	#9
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: What CFM is this carb? Jokers69....what a nice thing to post. I had seen that info before, but my damaged brain didn't dig it out of the annals of time, where it was buried. So, it looks like a 1970 Chevy Q-Jet for an automatic, without saying which engine it was on. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.



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