What carb for 440

[Geoff 2]

Houle,
You have made some very sensible comments in post # 52. Sometimes smaller is better because it provides better overall performance.
Overall in this context means from idle rpm up to the usable rpm that engine is comfortable with.

 

[BSB67]

I have a mild build 440 .03 over 440 source aluminum heads, hydraulic roller .600 lift intake .584 exhaust [email protected] 235/250 Edelbrock performer RPM intake stock exhaust manifolds 4 speed w/3:54 dana and I'm running a Edelbrock 650 AVS-2 and this car flat out runs. The only thing I changed on the carb was the factory red springs to the pink springs and changed the secondaries from.098's to .104's and this car pulls hard. Lots of people have said the 650 is too small until they can't catch me. It's easier to over carb than under carb

Good to hear that you are happy with your setup. Sound like it’s running great.

That said, don’t for a moment think that you are not leaving meaningful power on the table. I get that for many, that’s not a big deal.

 

[Krooser]

I realize I’m going to get a ton of different answers with this one, but im looking for some suggestions on what type of carb to go with. Engine is a 440, 10:1 compression with a voodoo 703 cam. It has TTI headers, a performer intake, 727 transmission and 355 gears. It has a reman Quadrajet on it right now and im tired of messing with it trying to get it idling smoothly. I’m leaning towards Holly or quick fuel, definitely something with vacuum secondaries. Any help pointing out the pros or cons of different carbs or what CFM size I need would be appreciated.

The stock AFB on my 413 was 570 cfm. It was designed for all driving situations, good fuel economy in a heavy car and adequate performance.

Most guys way over carburate their engines.

I wouldn't run anything over a 650.

Those online cfm charts, on the other hand, hopelessly underate the size of a carb needed for a race car. While the charts indicate I needed a a 750 for my dirt car my 388" was faster on an 850 or 900 @ 7000 rpm.

 

[davidplymouth1@]

I figured everyone would have a different opinion lol. Anyone have any experience with a Holly Street demon?

Lol -Yeah - a ton of different answers. My school of thought after 40 years is simply this. If u like simple - go with an Edelbrock - If you don't mind occasional tuning, a Holley will deliver noticeably better performance. But the Holley has an internal "power-valve" (that Edelbrock does NOT have) and it can be easily blown out if it ever back fires through the carb. It'll never tune right with a bad power-valve. A power-valve can be replaced easily but requires partial diss-assembly of float bowls and metering blocks. Again - simple or not so simple guides my decision making for carbs. A 750 - 800 is plenty of CFM on a 440 with a less than 600. lift cam. But it will easily handle an 850 -900 too. You just won't use all of the 850 -900 cfm. Good luck.

 

[Curiousyellow71]

Most if not all Holleys have power valve protection now. It was true about blowing a power valve 40+ years ago(not sure as to when they solved it).

The 440 sixpack carbs combined are 955 cfm when converted to a holley 4 barrel cfm rating.
I don't think too many six pack owners would trade for a 650 cfm carb.
But if anyone wants 2..I would be glad to trade a 650 for six pack carbs.Lol
That six pack is going to be way to big for your 440...its not going to be responsive at all..you will hate it.

 

[RemCharger]

Most if not all Holleys have power valve protection now. It was true about blowing a power valve 40+ years ago(not sure as to when they solved it).

The 440 sixpack carbs combined are 955 cfm when converted to a holley 4 barrel cfm rating.
I don't think too many six pack owners would trade for a 650 cfm carb.
But if anyone wants 2..I would be glad to trade a 650 for six pack carbs.Lol
That six pack is going to be way to big for your 440...its not going to be resposive at all.

Well stated.
And, a PV can be changed much faster than tearing an edelbrock apart.

 

[BSB67]

I love the “850 is way to big for a 440” statements we hear from time to time.

A simple look at historic facts. In 1969, Mopar took a std 440 hp engine, changed nothing more than the 750 AVS for a Six Pack, and corresponding intakes, and the power output increase was tremendous.

 

[Some Car Guy]

I love the “850 is way to big for a 440” statements we hear from time to time.

A simple look at historic facts. In 1969, Mopar took a std 440 hp engine, changed nothing more than the 750 AVS for a Six Pack, and corresponding intakes, and the power output increase was tremendous.

Same guys will tell you a 750 on a 383 is a bad idea. Lmao

 

[Geoff 2]

And how many DECADES did it take Holley to add PV protection?????

 

[Geoff 2]

Gee, there is some ignorance out there.....
The 6 pack made 15 hp more than the 4bbl. I wouldn't call 15 HP a tremendous increase.
Replacing the stock 4 bbl intake with a high rise intake like the RPM, with the stock 4 bbl carb, would more than likely have picked up most if not all [ or more ] of the 15 hp. The 6 pack intake was a true high rise design; compare it to the low slung stock 4 bbl intake, & it is easy to see the improved flow of the 6 pack runners, & not necessarily the extra airflow, made a big impact.
In factory parts testing, a SD Pontiac 455 made 451 hp with a SINGLE 800 QJ. When the QJ was swapped for a Holley, it made 12 hp more, but lost 13 ft/lbs of tq.... Just an example of a single carb, not multiple carbs, making 400 + hp.

The OP is using stock exh manifolds. That is going to severely limit the engine's breathing ability & it will not need such a big carb......
Big[ger] carbs do not automatically mean getting from point A to point B faster. If the VE of the engine is low, then it doesn't need more carb flow. Many factors to consider. With a bigger carb, might rpm quicker above 4000 rpm....but be a slug getting to 4000 rpm.

 

[BSB67]

Only if you choose to believe the factory hp ratings. Most of the creditable evidence suggests it is more, even from Ma Mopar itself, if you choose to look.

Your point on the intake is fair.

Your point on the exhaust manifolds and carb size is generally wrong in the context of this discussion. Certainly there is a hp price to pay using exhaust manifolds verses headers. At 400 hp, the price is small, at 600 hp, considerably more. To think that the hp gain with a large carb and headers will be more than a large carb and manifolds is reasonable, But to think that exhaust manifolds won’t allow a meaningful hp increase with a big carb is silly.

What folks want in “performance” from their muscle car is certainly a personal thing. Go ahead with small carb to really sharpen up that 1800 rpm throttle response and leave WOT hp on the table if that’s what you want. Myself, I prefer my muscle cars to be fast as they can be for what they are, and gladly give up a little low speed response for the better WOT power/acceleration. I have other cars for that. But that’s me.

 

[Cranky]

Gee, there is some ignorance out there.....
The 6 pack made 15 hp more than the 4bbl. I wouldn't call 15 HP a tremendous increase.
Replacing the stock 4 bbl intake with a high rise intake like the RPM, with the stock 4 bbl carb, would more than likely have picked up most if not all [ or more ] of the 15 hp. The 6 pack intake was a true high rise design; compare it to the low slung stock 4 bbl intake, & it is easy to see the improved flow of the 6 pack runners, & not necessarily the extra airflow, made a big impact.
In factory parts testing, a SD Pontiac 455 made 451 hp with a SINGLE 800 QJ. When the QJ was swapped for a Holley, it made 12 hp more, but lost 13 ft/lbs of tq.... Just an example of a single carb, not multiple carbs, making 400 + hp.

The OP is using stock exh manifolds. That is going to severely limit the engine's breathing ability & it will not need such a big carb......
Big[ger] carbs do not automatically mean getting from point A to point B faster. If the VE of the engine is low, then it doesn't need more carb flow. Many factors to consider. With a bigger carb, might rpm quicker above 4000 rpm....but be a slug getting to 4000 rpm.

The 6 pack made 15 hp more than the 'factory' rating. How did the factory rate them back then? I've heard they made much more than 15hp more but this would be for a different thread.

 

[JC Boatguy]

MaryAnn or Ginger.View attachment 1578631

Mary Ann!!!!!!!!

 

[JC Boatguy]

I prefer The Holleys because many of the tuning difficulties have been solved. In other words, I have a new 750 Brawler vac sec. On my 383. The jets can be changed from the top and the secondary Spring adjustment is a screw now, both floats bowls have a sightglass and center inlets. No more taking bowls off! Other than slightly less power off line, on a hard jab to the throttle, it winds excellent to 6000

 

[RemCharger]

Only if you choose to believe the factory hp ratings. Most of the creditable evidence suggests it is more, even from Ma Mopar itself, if you choose to look.

Your point on the intake is fair.

Your point on the exhaust manifolds and carb size is generally wrong in the context of this discussion. Certainly there is a hp price to pay using exhaust manifolds verses headers. At 400 hp, the price is small, at 600 hp, considerably more. To think that the hp gain with a large carb and headers will be more than a large carb and manifolds is reasonable, But to think that exhaust manifolds won’t allow a meaningful hp increase with a big carb is silly.

What folks want in “performance” from their muscle car is certainly a personal thing. Go ahead with small carb to really sharpen up that 1800 rpm throttle response and leave WOT hp on the table if that’s what you want. Myself, I prefer my muscle cars to be fast as they can be for what they are, and gladly give up a little low speed response for the better WOT power/acceleration. I have other cars for that. But that’s me.

Very good summary for the uneducated.
F.A.S.T cars run manifolds.. do some make 800hp? Some maybe more.

Torque does have advantages. Towing trailers, going up hills, winn8ng the first 200' in an actual contest of speed.
Personally I enjoy winning at the far end of the track.

 

[Cranky]

Very good summary for the uneducated.
F.A.S.T cars run manifolds.. do some make 800hp? Some maybe more.

Torque does have advantages. Towing trailers, going up hills, winn8ng the first 200' in an actual contest of speed.
Personally I enjoy winning at the far end of the track.

Those guys extrude hone their manifolds though, right? Still not as good as headers imo.....

 

[RemCharger]

Those guys extrude hone their manifolds though, right? Still not as good as headers imo.....

Agreed,
And REALLY agreed.

 

[BSB67]

I don’t know what the FAST guys are doing, but doubt that the key to their success lies in extrude hone. Also suspect that the cars are pretty light and probably puts most of the non-hemi big block cars (A12 cars), in the 650 hp range. All guesses.

I do know that nothing more than a little amature porting of the exhaust manifold at the port window will support 600 hp on a pump gas motor.

 

[Curiousyellow71]

Well...IF I am remembering right I got this off of Bill Diciccio FB page I follow. I believe his is right around 600hp w his 512 B(?) F.A.S.T. build with a iron intake with a AVS on top in his sleeper Roadrunner. Hoping he gets in the 10s this year. He was last on this site dec 10.
@Cudadude2 No extrude honing..just grinding.
..Wishing a happy New Year and more speed for everyone in '24!

 

[Cranky]

I don’t know what the FAST guys are doing, but doubt that the key to their success lies in extrude hone. Also suspect that the cars are pretty light and probably puts most of the non-hemi big block cars (A12 cars), in the 650 hp range.

I'm sure that porting the exhausts isn't the whole story....been awhile ago since I fell off of a turnip truck but did stay at a Holiday Inn recently