What size carb do you have on your 440 ?

Revhendo · May 12, 2011

Cranky said:
I guess I'm one that breaks all the rules by running single plenum intakes and DP carbs on street cars. Most of my streeters were stock block engines with headers, very small cams, around 3.55 gears and most of them were heavy with automatics with slightly better than stock stall converters. A few of them were pickups too. If you can borrow a buddies carb, you can do some testing but I would say the 850 is a bit big for a mild engine. Keep in mind that DP's get pretty lousy mpg numbers in town....

Not all of the rules, just a few. Question, do you think your mileage would've been better with something other than a DP?

1969 charger rt · May 12, 2011

On my motor i have a 1000 cfm hp holley but i have more motor than you do

Revhendo · May 12, 2011

1969 charger rt said:
On my motor i have a 1000 cfm hp holley but i have more motor than you do

Bwa ha ha ha ha. Are we compensating?

ink banana:

67 B-body · May 12, 2011

850 DP Holley on mine

696pack · May 12, 2011

The decision between vacuum and mechanical is driven by the cam size not the cubes or the weight of the car. Think about a Hemi, the factory supplied them with linkage on the dual quads coming in progrssively. If you put a bigger cam in then you can set the linkage up for mechanical.

Vacuum secondaries are much better on the street. As stated previously, there will be a bog with the mechanics. Yes, you can play with it with the shifter but you are losing time down shifting whereas with the vacuum secondaries it feeds the engine as it needs it for smoother power transition. Don't be fooled by the big thrust feeling when you downshift and nail it, as the guy next to you will be walking away with the same car and engine.

Revhendo · May 12, 2011

696pack said:
The decision between vacuum and mechanical is driven by the cam size not the cubes or the weight of the car. Think about a Hemi, the factory supplied them with linkage on the dual quads coming in progrssively. If you put a bigger cam in then you can set the linkage up for mechanical.

Vacuum secondaries are much better on the street. As stated previously, there will be a bog with the mechanics. Yes, you can play with it with the shifter but you are losing time down shifting whereas with the vacuum secondaries it feeds the engine as it needs it for smoother power transition. Don't be fooled by the big thrust feeling when you downshift and nail it, as the guy next to you will be walking away with the same car and engine.

Better than I could ever say. (Apparently). It should also be noted that it should all be considered as part of a combination. You don't just slap a tunnel ram on a 318 and expect the car to be 2 seconds faster.

Revhendo · May 12, 2011

Oh oh oh. I forgot to mention. On my 73 Roadrunner, with the 440 and 4 speed, I am running a Holley 750 vacuum secondary carb. To add to my further disgrace, I am running a vacuum advance on my distributor.

Meep-Meep · May 13, 2011

Revhendo said:
Oh oh oh. I forgot to mention. On my 73 Roadrunner, with the 440 and 4 speed, I am running a Holley 750 vacuum secondary carb. To add to my further disgrace, I am running a vacuum advance on my distributor.

And I am running a worthless factory cast iron intake with a 750 AFB, vacuum advance and a cam that most people wouldn't recommend to use as a hood prop on a Volvo. I didn't want you to be disgraced all by your self.

Meep-Meep · May 13, 2011

I believe more in the combination of engine and car. It all has to work. I have had great success with a 700 DP and a Torker on the street in a 383 powered B body with a 4 spd.

Regarding the factory multiple carb setups such as the HEMI and six pack. Part of what makes that work is a divided plenum dual plane intake. This sort of fools the engine into thinking it has a smaller carb/s by allowing half the cylinders to pull from only half the carb/s.

696pack · May 14, 2011

Meep-Meep said:
I believe more in the combination of engine and car. It all has to work. I have had great success with a 700 DP and a Torker on the street in a 383 powered B body with a 4 spd.

Regarding the factory multiple carb setups such as the HEMI and six pack. Part of what makes that work is a divided plenum dual plane intake. This sort of fools the engine into thinking it has a smaller carb/s by allowing half the cylinders to pull from only half the carb/s.

This is true but as with most things when building an engine the carbs and intake need to be matched for the particular intended driving.

Factory hipo street cars are very well engineered for maximum performance and daily driveability. As soon as you start changing things there are going to be compromises for you to consider and generally you are going to have to put up with some less than desireable street manners.

Cranky · May 14, 2011

Revhendo said:
Not all of the rules, just a few. Question, do you think your mileage would've been better with something other than a DP?

Sure but I was into hot rodding more than I was into mileage. Actually, my Mustang with the 289 got 21 out on the road but only about 12 in town. My 71 340 Cuda got 17 average in town with a TQ. Now that was a sweet carb.....

Revhendo · May 15, 2011

Cranky said:
Sure but I was into hot rodding more than I was into mileage. Actually, my Mustang with the 289 got 21 out on the road but only about 12 in town. My 71 340 Cuda got 17 average in town with a TQ. Now that was a sweet carb.....

Oh how I love those Thermoquads. It's one of the reasons I went with a Holley Strip Dominator intake on my stroker small block. It's one of the few single planes that will accept a spreadbore carb. (Got a friend who has a Superquad in a box on the shelf. I'm constantly pestering him for it).

In it's last configuration, 417 cubes, solid flat tappet cam (.550 lift/236 dur. 108 center) 10.5 comp., Comp rollers. I actually got 16 mpg on the freeway.
In the Roadrunner. Broke some valvesprings, wiped a lifter, lost oil pressure. So in went the 440 4speed. The little stroker is getting gone through and will live again. In my Valiant. (Insert evil laugh here).

Gonna miss that 22 mpg slant six.

69_roady · May 17, 2011

JUST PICKED THIS ONE UP ON EBAY
holley 750 double pumper pro form center new dyno tuned

combatsp · May 22, 2011

Here is a mathematical formula I found that may help.

Carb CFM = 440ci X max RPM/3456 X .80 V.E.

by the way, the .80 is the volumetric efficiency of the engine. 75% is for a stock engine and 110% is for an all out race engine. You have a mild cam so I estimated 80% converted to a decimal is .80. Leave out the V.E. to find out what the max CFM the engine can handle if it were higher performance.

Cranky · May 22, 2011

I've used that formula too but the hot rods always go a bit faster with a little more carb than what the formula calls for....

WileERobby · May 22, 2011

696pack said:
The decision between vacuum and mechanical is driven by the cam size not the cubes or the weight of the car. Think about a Hemi, the factory supplied them with linkage on the dual quads coming in progrssively. If you put a bigger cam in then you can set the linkage up for mechanical.

Vacuum secondaries are much better on the street. As stated previously, there will be a bog with the mechanics. Yes, you can play with it with the shifter but you are losing time down shifting whereas with the vacuum secondaries it feeds the engine as it needs it for smoother power transition. Don't be fooled by the big thrust feeling when you downshift and nail it, as the guy next to you will be walking away with the same car and engine.

Sorry, but the weight of the car has very much to do with the decision of the type of secondary. If you don't believe me, look it up.

696pack · May 28, 2011

WileERobby said:
Sorry, but the weight of the car has very much to do with the decision of the type of secondary. If you don't believe me, look it up.

And just WHERE would I look this up?

The bottom line is that there is always a trade off when you are looking at street and race use. Most people want a balance of BOTH. In that case YOU have to decide how much you are going to give up in STREET manners. My point above is based on what the factory determined was on the edge of acceptable street manners for the maximum performance.

Revhendo · May 28, 2011

696pack said:
And just WHERE would I look this up?

The bottom line is that there is always a trade off when you are looking at street and race use. Most people want a balance of BOTH. In that case YOU have to decide how much you are going to give up in STREET manners. My point above is based on what the factory determined was on the edge of acceptable street manners for the maximum performance.

Ah, but with the advances in technology, those boundries have changed. I just put a 605hp LS9 in a GTO that is way faster and more user friendly than the 421 tri-power that was in it ever hoped to be.

696pack · May 28, 2011

Revhendo said:
Ah, but with the advances in technology, those boundries have changed. I just put a 605hp LS9 in a GTO that is way faster and more user friendly than the 421 tri-power that was in it ever hoped to be.

And all of the these advancements can be explained in the most part in 4 words. Fuel injection, supercharged-turbocharged.

Revhendo · May 28, 2011

696pack said:
And all of the these advancements can be explained in the most part in 4 words. Fuel injection, supercharged-turbocharged.

Or three letters, ECM.

What size carb do you have on your 440 ?

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

дворянин

дворянин

Well-Known Member

Banned Henchman #27

Well-Known Member

Member

Attachments

Well-Known Member

Banned Henchman #27

FBBO Gold Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Similar threads