Need help - What size carb to go with? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jimbotronics · 08-10-2004, 07:52 AM

I currently have a 2bbl carb set up on my 71 350, it runs out nicely but seems to be sluggish on take off - I want to change the carb over to a 4bbl setup for better power/throttle response but not sure what size to go with. I want the truck to have nice throttle response and haul ass but I'm not trying to build a racer. I'm thinking a 600 to 650CFM. Gimmi some opinions please.

Tx Firefighter · 08-10-2004, 07:57 AM

600 cfm and make sure it has vacuum secondaries.

Jimbotronics · 08-10-2004, 08:06 AM

Thanks! Also, the current carb is a manual choke - what's involved in changing it over to an electric and should I change it or just leave it manual?

Jimbotronics · 08-10-2004, 08:08 AM

I would assume that it just needs power that's controlled by the eginition switch.

67chevemall · 08-10-2004, 08:30 AM

Manual Chokes are great just leave it!
Then you control the helm!
Cheers

Tx Firefighter · 08-10-2004, 11:47 AM

I only do electric chokes myself. A switched power wire is all it takes.

By the way, when I said vacuum secondary, lots of folks think only of Holley, but all Carter, Edelbrock, and Rochester 4 bbl are vacuum secondary.

cdowns · 08-10-2004, 02:00 PM

sounds more like a timing/tuneup issue you have .

Jimbotronics · 08-10-2004, 02:41 PM

Figured that mostly likely had a lot to do with it as well - I'll be changing the wires, plugs, cap, and rotor this weekend. I know what the timing is but don't have a timing light or know how to use one if I had one. Hopefully one of the guys I work with can help me out on that one. Anything I need to change besides what I mentioned?

cdowns · 08-10-2004, 03:45 PM

if you still have the original distributor you should change the points and condensor

and changing to a 4barrell usually means changing the manifold and to do that requires removing and reinstalling the distributor. a timing light and dwellmeter is pretty much required

ChevLoRay · 08-10-2004, 06:08 PM

Edelbrock Performer and Edelbrock Q-Jet. It's what I have and I like it.

08-10-2004, 07:52 AM	#1
Jimbotronics YA YA Join Date: Aug 2004 Location: Rockledge, Fl Posts: 1,273	Need help - What size carb to go with? I currently have a 2bbl carb set up on my 71 350, it runs out nicely but seems to be sluggish on take off - I want to change the carb over to a 4bbl setup for better power/throttle response but not sure what size to go with. I want the truck to have nice throttle response and haul ass but I'm not trying to build a racer. I'm thinking a 600 to 650CFM. Gimmi some opinions please.

08-10-2004, 07:57 AM	#2
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	600 cfm and make sure it has vacuum secondaries. __________________ I'm on the Instagram- @Gearhead_Kevin

08-10-2004, 08:30 AM	#5
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Manual Chokes are great just leave it! Then you control the helm! Cheers __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

08-10-2004, 11:47 AM	#6
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	I only do electric chokes myself. A switched power wire is all it takes. By the way, when I said vacuum secondary, lots of folks think only of Holley, but all Carter, Edelbrock, and Rochester 4 bbl are vacuum secondary. __________________ I'm on the Instagram- @Gearhead_Kevin

08-10-2004, 02:00 PM	#7
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	sounds more like a timing/tuneup issue you have . __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

08-10-2004, 08:06 AM	#3
Jimbotronics YA YA Join Date: Aug 2004 Location: Rockledge, Fl Posts: 1,273	Thanks! Also, the current carb is a manual choke - what's involved in changing it over to an electric and should I change it or just leave it manual?

08-10-2004, 08:08 AM	#4
Jimbotronics YA YA Join Date: Aug 2004 Location: Rockledge, Fl Posts: 1,273	I would assume that it just needs power that's controlled by the eginition switch.

08-10-2004, 02:41 PM	#8
Jimbotronics YA YA Join Date: Aug 2004 Location: Rockledge, Fl Posts: 1,273	Figured that mostly likely had a lot to do with it as well - I'll be changing the wires, plugs, cap, and rotor this weekend. I know what the timing is but don't have a timing light or know how to use one if I had one. Hopefully one of the guys I work with can help me out on that one. Anything I need to change besides what I mentioned?

08-10-2004, 03:45 PM	#9
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	if you still have the original distributor you should change the points and condensor and changing to a 4barrell usually means changing the manifold and to do that requires removing and reinstalling the distributor. a timing light and dwellmeter is pretty much required __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

08-10-2004, 06:08 PM	#10
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Edelbrock Performer and Edelbrock Q-Jet. It's what I have and I like it. __________________ 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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