2bbl to 4bbl swap

i just swapped my original 2bbl to a 4bbl and changed the intake to a 4bbl intake. the question is when i hook all of it up will the engine bog and run rich or will it handle it correctly?

 

Just tune the carb and it will run great.

 

it will depend a lot on how big a carb you put on it.

 

Ditto, it also depends on what carb, what intake and how you tune the motor for the new setup. Just bolting it all together and expecting great things to happen is probably not going to be what you expected. For example, bolting on a Vic Jr intake and topping it with an 850 Holley DP carb on a stock 302 is a guaranteed loosing proposition. Going with a Edelbrock Performer RPM topped with a Holley 570 Street Avenger onto the same engine will give you excellant results after it's all tuned.

 

You guys act like if he's gonna try and put a Dominator on a it.

 

How do you know he didn't ? He gave no specifics, just a general question. And I gave him a realistic answer.

 

Well I don't know, but you guys should at least wait for him to chime in

and you know the odds are like 90% that its going to be your typical 600CFM unit.

 

Yea, then there are those who buy into the "bigger is better" approach to parts picking, which doesn't always work, especially when it comes to carb sizing.

 

I'm with you on that.
A stock engine that only makes power up to 5K only needs 305CFM if its at 70% efficiency.

That's why these engines can get away with 2BBL from the factory.

 

I used a 500 cfm holly 2brl on my 302 small cam mustang and love it, I see no need for more carb...

 

A bigger carb doesn't necessarily mean it's more carb. Just because its rated at a certain CFM doesn't mean it will flow that CFM at all engine speeds.

And going to a 4BBL(with smaller primaries) would save you a few MPG's over a 2BBL IF you can keep your foot outta it


But for sheer power those 2300's are awesome

 

i actually went with a street ready 4 bbl so i could have the power when i wanted it and the mpg when i didnt its rated 600 cfm and its just a holley street carb

 

That's a good easy way to more power. I've had several Holley 500's over the years, all were great, reliable carbs.

 

They flow rate 2-bbl carbs differently than 4-bbl carbs so you can't really compare them, and neither method has anything to do with how a carb will flow on an actual running engine...

 

Right ! :Handshake FYI: The Holley 500 2 bbl is exactly half a 750 double pumper 4 bbl carb. The 2's are measured at 3"hg drop, the 4's at 1.5"hg drop. The center 250 cfm 2 bbl on my 3x2 setup flows about 325 cfm @ 4500 rpms before the secondaries are opened.