F85 330 ctls

I have a 67 f 85 cutlass 330 2 barrel carburetor car,what 4 barrel carburetor can I install for better power? and will I need a new intake also,I just want a little bit more power,any ideas that won’t break my wallet to much.

Fun71

You will need a 4bbl intake manifold. Any Olds small block 4bbl intake will fit onto your engine, either aftermarket aluminum or cast iron factory. For a 4bbl carb you will also need a different air cleaner housing as the 4bbl versions have a larger diameter hole to fit the carburetor.

Which intake and carb depends upon if you want to keep the car factory original looking or if you don't mind using aftermarket parts.

oldcutlass

Your also going to have to adapt throttle linkage and make sure your switch pitch/down shift adjustments stay in check.

F85 330 ctls

Thanks you for the info

droldsmorland

Dont rule out the venerable 2GC Rochester. Circle track guys use them.
Depending on the model number they range from 220 ish up to 430 ish cfm (Commonly called a 500cfm). With a low restriction air cleaner and exhaust along with a proper tune on the fuel and ignition system that 330 should be able to do a burnout.

Induction upgrades alone without upgrading cam, ignition, exhaust, and gearing is a waste by itself...IMO.
It all needs to be upgraded as a "matching package" to really see any benefit besides reduced gas mileage.

joe_padavano

Just to clarify, circle track guys use the 2bbl because class rules require it, not because it's the carb they would prefer. They'd like to have an extra 100 cu in also.

Also, there's a big difference between a race motor that is optimized to run at a narrow RPM range and a street motor that needs to make good power from idle to 5000 RPM. Even at the same CFM rating, a 4bbl with four smaller bores will be a more responsive carb on the street.

And finally, don't be fooled by 2bbl CFM ratings. 2bbl carbs are rated at 3 psi pressure drop across the venturi. 4bbl carbs are rated at 1.5 psi pressure drop. Higher pressure drop means higher measured flow - test a 4bbl at 3 psi drop and the flow rate will go up dramatically from the carb's rating. You can't compare 2bbl CFM ratings with 4bbl CFM ratings.

Fun71

I agree that the engine needs to be tuned after a carb swap, but the factory numbers for the 1972 350 engine shows measurable power increases from 2bbl to 4bbl for both single exhaust and dual exhaust. I'm sure the differences are similar for the early 330 engine as well.

Engine.....Carb.....Exhaust.....HP @ RPM.....FT-LBS @ RPM
350.........2-bbl .......single .....160 @ 4000 ....275 @ 2400
350.........4-bbl........single......180 @ 4000.....275 @ 2800

350.........2-bbl........dual........175 @ 4000......295 @ 2600
350.........4-bbl........dual........200 @ 4400......300 @ 3200

OLDSter Ralph

Fun71, I am sure what you have shown is similar to every year back into the 50's. Going from a 2 barrel to a Quadrajet would make a noticeable difference on a 330.

joe_padavano

It also demonstrates that an engine is a system and all the parts need to match for optimum performance. The numbers show that going from single exhaust to dual exhaust with a 2bbl only provides a 15 HP increase. Going from single to duals with a 4bbl provides a 20 HP increase. I know this is a cliche, but an engine is an air pump. Flow more air through the motor and you make more HP. That means that you have to increase airflow on BOTH the intake and exhaust sides to maximize HP. Sure, I understand that the real world often requires one to make modifications incrementally. Just do that with an eye towards the desired end state.

pav8427

Dont rule out the quadrajet. Good stock rebuild on one off a similar sized motor should work for your app. Avoid remanned units. They tend to be messed up. Find a good clean core, rebuild stock, and fine tune from there. Have to use some special stuff for early intakes with heat riser holes in carb mounting flange. Would shoot for a early 70's unit.

redoldsman

The OP doesn't say if he has dual exhaust or not. If not, that is the first thing I would take care of. I don't know how the horsepower increase compares but his butt dyno will give better performance with a good set of dual turbos.

pav8427

Forgot to mention. Should be able to find later quad with e choke already on it. They have the desired APT in the air horn that adds a little ease to tuning.

TripDeuces

Where are you located?