HELP...Need answer about carbs ASAP

[jmacintosh]

I have a 350 mouse set up as a daily driver. I have a Holley 650 Double Pumper I may be able to re-jet to tone it down a little.

Anyone have a good suggestion for a replacement? Dare I say the word quadrajet?

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

Edited by: jmacintosh at: 5/4/06 8:23 am

[1976Scottsdale]

Well, you won't ever get chewed by me about Quadrajets, they are my favorite.  I have one on the shelf right now waiting to be put back in to replace my Edeljunk 600CFM electric choke.  If you get a quadrajet set and tuned correctly, it will be the best thing you have ever used.

[jmacintosh]

I currently have an Edelbrock Performer intake. What would be a good CFM rating to go by for a Quadrajet carb?

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

[roundedline]

Typically a 750cfm with vaccuum secondaries will work just fine.  Unless you are turning more than 6000rpms, 650cfm is more than enough for a 350 engine.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

[jmacintosh]

Turns out I have one of these just sitting in the garage...

www.holley.com/0-80555C.asp

Would this work ok?

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

[drewmech]

ah if you look on ebay you can get a TBI set up (ecu, wiring, and injector pod) go on summit and you can pick up an adapter plate for the tbi to use your current manifold then if you to moates.net they'll sell ya the stuff to modify and tune the TBI using datalogging and any old cheap laptop the software is free. www.thirdgen.org and www.binderbulletin.org have all the info you need for this swap (www.binderbulletin.org is an international site but go to forums then fuel injection and it'll show you everything you need). as for the holley injector pod its not required (that and their injectors suck) just pick up an extra stock tbi pod for cheap off ebay or your local you pull it yard and just runnin down to your local machine shop they can open up your throttle bores.  

[jmacintosh]

I wasn't looking to get into TBI, just wanted to make sure I got the right carb for my application.

This won't be for a high performance machine, just a daily driver with a little better than stock performance.

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

[drewmech]

the 600 cfm edelbrock performer is all you'd need. most people go with way to big of a carb. 600 cfm is enough to feed most any stock to mild sbc.  

[jmacintosh]

OK...just heard from the mechanic...bad news...

He told me the carburator is not the correct one.

Apparently the original carb had 4 equal sized bores, and the Holley I had laying around has 2 large bores in back, with 2 smaller ones up front.

I either need to replace the intake, or get a new carb. I am not sure which model intake I have, but I believe it is an Edelbrock performer intake with the square bore. I never took the carb off to see which size bore it had. Oh well...

If anyone is interested in a nearly new Holley 650 (not dbl pump) let me know. Just beware it has the 2 large bores in back, and 2 smaller ones up front. I believe that is called spread bore?

Also...I do see alot of adapters available...would I be taking a mileage, or performance hit if I was to use an adapter to mate the spread bore carb, and the square bore intake? I have room to spare under the hood.

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

Edited by: jmacintosh at: 5/3/06 11:18 pm

[roundedline]

The original carb never had 4 equal sized bore if you are talking about original from the factory.  They all used Q-jet Spreadbore carbs.  Running a square bore will hit your mpg's.

You could run a spacer/adapter, not sure what kind of mileage difference it would be, but I never had good luck out of Holley spreadbores.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

[jmacintosh]

So am I better off getting a new spread bore intake to make everything match  properly?

Or, am I better off getting a different brand of Q-jet Square bore carb?

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

[Z28 c10]

You could easily run an adaptor. I've done it a couple times with sbc's. Just make sure you get one at least an inch tall, you should not have any hood interfearance, plus, if you look around thruogh Summit or Jegs, get the phenolic spacer. It acts as a heat sheild for that carb, the spacer isolates the intakes heat and keeps it out of the carb. Hot fuel does not atomize as finely as cold fuel. Cold finely atomized fuel and air make more power.

 JayTater

 Z28 C10

[1976Scottsdale]

Q-jets were sadly, never a squarebore carburetor(4 equal holes), they were only spreadbore.  I am running a Holley Street Dominator manifold right now and it will use the edelbrock or Spreadbore type. If you wish to run the holley, either spend about $120.00 on an Edelbrock #2101 manifold or buy an adapter.  I don't care for adapter plates myself, but it is up to you an your budget.