Newbie Question #9

[SonOfThomp]

Greetings!

Considering the 'ease' of going from a 350 2v to a 350 Qjet.

So, intake manifold-wise, which models - stock AND aftermarket - would accommodate the various bracket attachments (including a York-style aftermarket a/c) currently attached to a 1961 283 2v intake?


Thanks
SonOfThomp

 

[No409]

i just did a 56 chevy witha 350, 2bbl, no a/c.
i installed a edelbrock performer intake, edelbrock 600 cfm w/ elect. choke, pertronics in the dist.

what a wake up that did to the car!

cust cant believe power increase( it aint a rockedship, but goes a lot better!)

i would recommend leaning towards that way, than a q-jet

my 2 cents

 

[SonOfThomp]

I'm 'trying' to maintain a decent level of fuel economy - hence, the Qjet with the tiny primaries. I think, though, that the addition of two more barrels will affect the weight of my right foot. Honestly. I am quite open to suggestions on carbeuration, though, too.

I think I'll take the car with me when manifold shopping. A simple visual inspection will make it easier.

 

[jr.W]

Qjets will run hard when all is well with them.(Tight throttle shafts good
float needle & seat The usual stuff and the air door set properly)

 

[SonOfThomp]

Qjets will run hard when all is well with them.(Tight throttle shafts good
float needle & seat The usual stuff and the air door set properly)

Wondering what 4v would be the best all around choice/compromise between:

Economy (ha!)
Performance (oooh, YEAH) and
Low maintenance/reliability

 

[models916]

I Like......

I like the Holley Avenger for street use. Usually needs no calibration.

 

[SonOfThomp]

I like the Holley Avenger for street use. Usually needs no calibration.

Is this a 'racing carb'? I need it for everyday use.
Economy is a consideration, after all.

If it's a stock 350 crate motor (and that's all I can tell you), would 500 - 600 cfm be a good guess? Or . . . . ?

What is the cfm rating of the stock, 1961 Rochester 2barrel on it now?

 

[rwagon57]

The Holley Avenger is a street calibrated carb rated around 600 cfm. The 2-barrel is around 250 to 300 cfm. Other options are the Edelbrock carbs which are available in square flange configuration in various sizes from 500 cfm and up and in spreadbore (Qjet) style.

 

[SonOfThomp]

The Holley Avenger is a street calibrated carb rated around 600 cfm. The 2-barrel is around 250 to 300 cfm. Other options are the Edelbrock carbs which are available in square flange configuration in various sizes from 500 cfm and up and in spreadbore (Qjet) style.

Would 600 cfm, regardless of make of carb, be too high for a stock 350? What would be optimum? Sorry, I have no idea about comp"ratio or cam specs, but I'd suspect they're both on the mild side.

From what has been posted, the Rochester QJet sounds like it has to be *just so* in order to be a good choice, and the Holley Avenger is pretty rock solid. What are the pros and cons to each? And the Edelbrock?

 

[rwagon57]

For all around drivability, economy, and more "git" (highly technical term ) an Edelbrock Performer intake and a 500 cfm Edelbrock carb is very hard to beat and it will work just fine on your 350.

Holley has a similar manifold that would work as well.

If I was spending my money I would go with the Edelbrock set up, but that is because I am far more familar with Brand E carbs than I am with Holley's.

 

[Dick MacKenzie]

Would 600 cfm, regardless of make of carb, be too high for a stock 350? What would be optimum? Sorry, I have no idea about comp"ratio or cam specs, but I'd suspect they're both on the mild side.

SonOfThomp,
I'm sure there are a ton of carb calculators on the net. Here's one that's fairly easy. Most people over calculate their carb requirements. Most factory, normally aspirated engines have an efficiency of about 80%.

http://www.4secondsflat.com/Carb_CFM_Calculator.html

 

[SonOfThomp]

Thank you both for your input.

Here's what I got on the link sent by Dick mackenzie:

455 CFM required 100% VE
364 CFM required Used % VE (Ientered 80% per DM's advice)

That determined, which carb now?

Thx
SoT

 

[Dick MacKenzie]

SoT,
Using the calculator with 350 c.i., 80% v.e., and 5000 RPM I get about 445 CFM or about the same thing you did. Sounds like you are not intending to thrash it but use it strictly as a cruiser. That being said I would agree with rwagon57, a 500 CFM Edelbrock and the performer manifold should do a nice job and leave you a little room for a little more cam and maybe some head work in the future. Sounds to me like rwagon57 knows what he's talking 'bout!

 

[SonOfThomp]

Thanks, guys - this is a daily driver in the making, and the intake/carb changes have to wait for a front end rebuild. I will go Edelbrock 500cfm, when I make the change. And I will make the change - hopefully, the 15-16 mpg combined won't be afeected TOO much. Actually, that is something I can do myself, as opposed to the front end work. If only I can get my 20 month old daughter to help - or leave me alone for a spell.

Cheers
SoT