At around 3900lbs, 99mph to 104mph shows about a 55hp gain.

I guess I’ll have to add it to my long list of things I’d like to try on the dyno someday.

We rebuilt a 440-6 to basically stock specs last year.
2355 pistons, rebuilt 906’s(zero porting), felpro head gaskets, heads just milled the minimum, but it got a Howard’s 720141-12 cam(279/289, 225/235-112, .490/.488), and it was dynoed with 1-7/8” headers but without the air filter assy.
Made 410hp.

Mopar Muscle did an article on one about 2 years ago, pretty similar build, used a Comp 270h cam, made basically the same power.

my r/t weighed 4060lbs with me in it weighed at the track. with the last combo I had in it I believe horsepower was in the 410-415 range with 107.5-108mph trap speeds. ironically on the chassis dyno the engine was pretty much done at 4300rpm and fell off the cliff at 5300rpm. I shifted around 5200rpm. fuel delivery is a big deal with the 6pak. I do believe the kb184 piston makes more power than the stock 2.03 pin height 10:1 piston.

451 low block 452 heads D.C. Pocket ported. KB reverse dome 10.6 compression. Port matched and Vanke mod low deck cast iron intake 440 AVS carb. Hughes 224 230 at .050 .504 intake .515 stock rockers. Stock hp exhaust manifolds. 3900 lbs Bee, 11" dynamic 4.10 gear. 12.42 at 111 and change. 20 years ago. Had a lot of people scratching their head.

I took a bunch of old track test data from several magazines for 440s and using test weight, mph and weather conditions, correcting to std conditions, they were in the 300 range. I don't think any of the 4bbl cars broke 100 mph. Like Lew said the DC book called them 275 to 320.

Back in 1990 we were talking even back then how hard it would be to truly replicate a factory 440. If you want to try Dwayne, ill toss in the 2.03" (+0.030) pistons.

When we swapped out a factory TQ intake with a Holley 800 cfm spreadbore carb to my 6 bbl set up on a stockish 440 it picked up 2 mph, from about 102 to 104.

My opinion is a truly stock 440 with a well tuned 750 avs/afb Probably gives up 20 - 25 HP to the 6 bbl. But once you do just a little more to the engine, the 4bbl intake has no more to give as it is the limiting factor, where as the 6bbl is not. Add a little cam and better head to 6bbl motor and it mighty pick up 30 or 40 HP but on a factory 4bbl maybe only 15-20 HP.

That 440 I started 4 years ago I was planning to do a bunch of track testing of intakes and carbs on a 425 - 450 HP potential motor. Maybe ill get back to it.

Not a 440 but back in the August 2017 issue ( I think ) Mopar Muscle dyno'd the 340 they built to basically stock specs but had roller tip rockers and mild bowl blending. It made 320 hp with stock intake , carb , cam specs and exh manifolds. They added the 6 pack setup and made 356 hp with no other changes. Ron

I would have loved to hear about the engineering and testing that went into developing the A12 six pack package.

Sort of...

After Dulcich did his big 440 intake comparison which IIRC included an OEM iron 4-bbl, he did another article where he tested a 6-bbl on the same engine to see how it compared with a Performer RPM and a Holley 830 HP.

Once he stuffed enough jet into the outboard carbs, the 6-bbl made a few more HP than the Performer RPM combo.

I suppose if you could find both articles online that there would be a way to compare the OEM iron intake with the 6-bbl. But it wasn't a stock 440 he dynoed, either, so the comparison would need some caveats...

I know this isn't really what you're after, but I changed manifolds on my old 10:1 906 headed (unported) 440 w/ the MP 509/292 cam that ran high 11s w/ a Performer RPM intake and 830 holley.
I had an MP aluminum M1 dual plane manifold (aluminum version of the stock HP intake) that I put on just for the hell of it w/ the same 830 holley. I didn't take it to the track, but the loss of power was astonishing. It felt completely neutered and was all done at a lil over 5k rpm versus the 6200-6300 or so RPM the RPM intake would pull. Really wasn't expecting that drastic of a power loss on such a mild engine.
After that, I could definitely see why the 6 pack cars ran so much better than the 4V cars.

I believe it! I took the 6bbl off my r/t and put the original stock stuff back on a few years ago and the power loss was tremendous.

I found another track test of a 375hp 440 in a '69 gtx automatic 3.91 gear car. best e.t. was 13.98 and best mph was 103.80. I consider this performance to be more of an exception than common place. I remember back in the late '60's, when pure stock racing really was pure stock, 375hp 440's would run in the lower half of 14 sec bracket. exceptions to that would be 14.00's to 13.90's at 100mph.

on another note here, who was the first to coin the phrase 6 bbl? ford in 1962 with their 3 carb 405hp 406.

found another track test (1970 hot rod magazine); '70 challenger, 375hp 440, auto, 3.55 rear, 3850lbs; 14.54@98.36mph. a little below average performance.

It's amazing what headers and a cam will do.

Stock '71 bottom end (ring and bearing) and stock 452 heads with a Holley pattern '67(?) Intake and 750 3310.9.5:1 CR.

Made 318hp to the rear tire.

I wish I had kept it long enough to play with intakes...

Fairly recently a friend of mine reringed and rebearinged the low mileage 440 in his 69 GTX. He put one of those resto camshafts in it as well. It ran 13.97 at 100MPH at Mission raceway. I think that was faster than an average one back in the day but Mission is a good track and this thing was as close to stock as you're going to get.

I have seen multiple references for a '69 GTX 440 4 speed 4.10 car that trapped 104, with a 13.7ish ET. It's been referenced in various coffee table type books, but I can't remember where I read it.

http://wildaboutcarsonline.com/cgi-bin/p...taldisplayed=50

This one had a 69 X with a 727 and 4.10s turning 13.7 @ 102.8, and a Charger 500 with a 727 and 3.55s turning 13.9 @ 101.4. That's a great website if you like reading through old road tests by the way!

It seems to me that most 440 B bodies with 3.23s and a torqueflite would trap 97-100 MPH, but that trap speed started gaining with more gear. I've seen tests with lower trap speeds, but honestly there doesn't seem to be that many. 98 MPH for a 440 4 barrel with 3.23s seems to be about par for the course.

I think the 6 pack setup is worth 2 MPH vs the stock intake and 4 barrel. It seems a good running 4 barrel car with 4.10s would trap 102-104, and a good running A12 car would trap 104-106. There are also plenty of tests from 70/71 B bodies with the 6 pack and a 727/3.23 combo and those seem to trap 99-101 MPH.

A friend bought a loaded '67 GTX convertible, 4 speed, brand new. He recalls running 14.60s-14.80s when it was stock, which he thought was pretty strong for a heavy convertible as it wasn't much off what hardtops were running.

when I was running my set-up I tried 3.23, 3.55, 3.91 gears. anything lower than a 3.23 didn't do anything. baffled by that the chassis dyno told the story. the engine was quitting around 4300rpm; went thru traps at 4300rpm with 3.23's, anything else was over gear. back in the day there was a dyno shop we'd go to and we all noticed that the engines/chassis combo's made far lower horsepower numbers at the wheels at much lower than max rated horsepower rpm. we were always baffled by this and didn't know how to explain it. I understand it all now. what an engine does on an engine dyno is one thing; what it does all hooked up to accessories/full exhaust/drivetrain is another.


all cam changes did was fatten up the torque curve with maybe a few more horses. I tried the stock magnum cam, comp cams 268/276 magnum replacement, 272/.455, and the engle 2330; engle performed best. the summit 6401 I later tried with the stock 4bbl set-up would have been very promising and may have been ideal for cast exhaust manifolds. the 6401 isn't made very well but does outperform it's price. howards has those lobes and could make a more accurate camshaft.

I have a 440 that was first built in the 80s, the short block was blueprinted and has 9.5 cr, the heads are 452 s with 2.14 /1.81 and have been pocket ported along with port matched. About five years ago I found all the parts for this motor cleaned them up and reassembled it and added a NOS 557 mech mopar cam I had and an old M1 and 850 Holley. There's nothing trick or hight dollar just trw pistons mopar rockers and MSD ign.

520 hp @ 5900
545 tq @ 4700

Everything else being equal, gear won't really change trap speed much. Maybe 0.5 mph, and it could go down.

I know gear didn't work on mine. cured me of the gear hype.

Okay, I found it. Looks I did this in 1989, and it was not corrected to std conditions.

In summary for 440 4 bbl cars:
1) Eleven 440 hp (67 through 70) track tests from various magazines.
2) All but one ran in the 14s, one a 15.2
3) All but two were <100 mph. The 69 'Cuda went 103.8 and a 70 Superbird went 103.7, but was tested on a 10°F day in Detroit with snow on the ground.
4) Uncorrected the Mopar "Drag Strip Dyno" horsepower had them from 252 to 360 hp (note, the DSD generates hp values about 20 hp higher than the Moroso calculator). The above referenced 70 Superbird had the 360, most of the rest were about 300 hp or lower.
5) Test weights were high due to extra test equipment and sometimes a second person. Range from 3780 to 4550. Only one was below 4000lb.

FWIW.

Also found these notes that you might find interesting.

This was in 1987 shortly after I purchased my 67 Charge. It had about 105,000 mile on it, and burned oil like crazy. For the motor, the only change from pure factory original was a refresh of the heads that included new replacement valves and new guides (hoping this would solve the oil consumption problem). It was AC equipped at the time and race weight was 4380 w/ driver. It was a cool spring day at Tri-State Dragway near Cincinnati OH (i.e. pretty good air). It ran 14.9, 14.8 and 14.6 at 93.1, 93.5, and 94.3 mph. My now wife said at the time that it smoked so bad she was a little embarrassed.