What size carb do you think i need?

[MadMax]

Hey guys, I have a basically stock 350 sbc in my monte carlo bored .030 over. Stock stroke, etc. I have some 4 valve relief flat tops in it, and bone stock 58cc heads. Currently it has an old gm 2 barrel intake and carb that matches the heads, but i feel that with the amount of compression that this thing has...i should really upgrade the breathing room a little. I have a factory qjet intake, but i'm not sure if i should just go all aftermarket. Your thoughts?

 

[GhettoRacingKid]

need to know a few things,

Cam
Compression
type of exhaust
header tube size

Everything needs to work together.

I would say a 650cfm is going to be more then enough for now

 

[RITTER]

If you have 4-valve relief flat-tops with 58cc combustion chambers ... you have way to much compression for a "stock" engine :idea:

 

[CHRIS.O]

If you have 4-valve relief flat-tops with 58cc combustion chambers ... you have way to much compression for a "stock" engine :idea:

Yea definitely. My guess would be 10.5-11.1 compression. Anyway if you have that type of compression I would look into changing a couple things. First and foremost get rid of the 2bbl intake. Edelbrock Performer RPM or Air Gap are my recommendations. As far as the carb, depending on the use of the car I would buy a Holley 670 Street Avenger assuming you just want to drive it and horse on it a little bit. If your gonna be always abusing it then you cannot beat a Holley 750 Double Pumper. If you know somebody who knows how to properly tune a quadrajet you could easily go that route as well, however an out of tune quadrajet is a piece of sh*t, more so than a Holley or Edelbrock in my opinion haha. Edelbrock Performer series carbs are also decent for driving and easy to tune. On to the next improvement. I would buy a cam that can use all that compression you have without getting too crazy.

 

[MadMax]

I think that the heads are factory 2 barrel heads, but i can't be sure. It doesn't like to go above 2500 rpm until its around 190 degrees, either.

 

[othtim]

Hey guys, I have a basically stock 350 sbc in my monte carlo bored .030 over. Stock stroke, etc. I have some 4 valve relief flat tops in it, and bone stock 58cc heads. Currently it has an old gm 2 barrel intake and carb that matches the heads, but i feel that with the amount of compression that this thing has...i should really upgrade the breathing room a little. I have a factory qjet intake, but i'm not sure if i should just go all aftermarket. Your thoughts?

If you have that kind of compression I'd think you're going to be into detonation if you increase your VE.... I think maybe the only thing keeping you from detonation right now is that 2 barrel! lol. or am I out to lunch on that? 10.5 - 11 on stock heads seems like too much - maybe get a thicker HG?

as for carb q's personally i'm a huge fan of q-jets. i dont find them that hard to work with, i dunno what everyone has against them, they seem pretty easy to deal with imo. and good fuel economy and great throttle response - what's not to like??

 

[MadMax]

As far as a cam goes, it's just a very small RV cam. Jegs long tubes, not much else.

 

[L92 OLDS]

For a relatively stock application you won't beat the performance and fuel mileage of a Q-jet. IMO, Holleys have thier place at the strip and from my experience, Edelbrock carbs just don't perform as well as the others. Q-jet nay sayers don't take the time to understand them. They are one of the best carbs out there.