2bbl to 4bbl

[Tskaarer22]

I wanna change from a stock manifold and 2bbl carb to a taller manifold with a 4bbl for more horse power. What the best route to go?

 

[Shenango]

Your question leaves a lot up in the air. The simple answer is to get a matched carb/manifold from Summit or Jegs.

By more HP do you mean a greater seat of the pants feel from light to light (torque) or do you want more top end.(speed)
To get more effective HP the intake and carb is just the start. To use the additional air through the carb you will need better flowing heads a better cam and less restrictive exhaust.

The easiest way to get better acceleration is to change to a shorter gear in the differential. If you go from a 2.41:1 rear gear to a 3.73:1 gear you will get increased seat of the pants feel for the least amount of money.

You didn't say what engine was in the car but any V8 will react the same to each of these changes.
Good luck, Jerry

 

[Tskaarer22]

I have a 1970 stock Catalina 400 with a 2bbl carb and single exhaust and it's time to replace the carb at the very least. Without a lot of disposable income I was just wondering about the benefits of switching to a taller manifold and 4 bbl carb.
Thanks in advance.

 

[melsg5]

You will get some increase in power but with a single exhaust, non-high performance cam and heads and rear end ratio slanted toward gas mileage, the full benefits of the carburetor and intake will not be achieved.

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[Tskaarer22]

So it's just best to go with the stock replacement carb?

 

[melsg5]

Are you saying your current carburetor requires replacement or rebuilding?
Your original post indicates you wanted a performance increase.

 

[Shenango]

For more smiles per dollar consider this.
1, Get a kit and rebuild your 2 bbl carb.
2, boost your timing about 8* +or- 2*
3, put lighter advance springs in your distributor
This can all be done for about $50.
Tuning these old cars is not an exact science but is a lot of fun and real rewarding when you get it right.

 

[Tskaarer22]

Are you saying your current carburetor requires replacement or rebuilding?
Your original post indicates you wanted a performance increase.

Yes the current carb requires rebuilding or replacement. With that in mind I was wondering of it was enough of an increase in performance to merit going with a 4bbl/manifold upgrade or best tho just rebuild or replace the 2bbl. Thanks for all the help.

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[melsg5]

Explore the cost and see if you think it's worth it.
Try Summit Racing and Jegs.

 

[avell007]

You will benefit more hp with a 4bbl swap your cam might be the 066 used on both 2bbl and 4bbl , I think that cam goes up to 330 400 (my motor) then after that they use the 067,068 in the gto 400's , if you can find a used stock set up it should be reasonable money wise vrs $400 for just a Edlebrock 4bbl intake. Please provide your block code its 2 letters left of the timing cover.