Stock six pack carb setups on stroker engines

Hello!

Just wondering how does a bone stock set of six pack carburetors would work on a stroker 440 with stealth heads and a hotter cam.

Will they work or will they be totally off???

What about on stroked small blocks???

Are the non adjustable idle needles (plugged) on the stock outboard carbs a problem? Do they need to be adjusted on stroker motors?

I had three different sets of Holley six pak carbs that I dyno tested on my pump gas 400 block pump gas 511 C.I. storker motor, the 1971 stock 440 carbs opened to soon so I had to change the outboard vacume pod springs to slow it down so it wouldn't bog They, six paks, rock on the street once you get them dialed in close I would remove the lead plugs on the outboard carbs to get to the idle mixture screws and turn them in gently to bottom them out and then unscrew them to 1/3 to 1/2 turn out from bottomed out and then use the center car. idle mixture screws for the final tuning Let us know how you like them

that's what I hear, I cant afford one myself but Domino I would jump right in & post how it turns out for you

I ran one on a 496 with Indy SR heads a few years ago. Changed the secondary vacuum springs as someone suggested, and someone I cannot recall who makes aftermarket secondary metering blocks that allow adjustment that I am sure you could find googling.... Been awhile so its from memory sorry.

Worked fine, but I think the issue is more with the manifold depending on how serious you are and your cam etc you give up a good chunk of HP on the top end. I know comparing the SR head intake ports to the manifold ports it was a HUGE size difference alone, not to mention the dual plane design. As a result I had what I considered some very decent overall power and low end, but had a disappointing peak HP number...

So on a "street" car with a reasonable converter and gears etc it worked great but on a "drag" car with a big converter, gears, cam where you are looking to make nothing but top end power I think you give up a lot versus a single plane and big single 4 barrel.

I have the DC mechanical carbs on a Hughes deep-ported factory-style aluminum sixpack intake on my 493" stroker motor. The combo can make some impressive top end power when set-up right.

Since the motor was dynoed, I've upgraded the rocker arms to 1.6 to 1 ratio T&D's with Manton pushrods. It gave me about .050" more lift and a touch more power everywhere especially on the top end. The motor still wants more cam, but I don't want to give up the power on the bottom end. It street driven 99% of the time, and already rev's like a small block.

Here are my dyno sheets contrasting the sixpack's performance with a big 4 barrel carb and intake. These numbers are with .050" less lift than it has now, but it is still a pretty healthy street engine.

http://www.hughesengines.com/TechArticles/3dynotest684hp500cid6pack4bbljcross012007.php

It isn't the carbs that kill off the power in a six pack setup it is the twists and turns inside of the stock intake. The porting helps and with a smaller cam like JBC has the numbers are close. In a street engine the dual plane design really helps with the low end torque. Flip over to a race engine and the dual plane kills off the high end power.

The NHRA super stock guys run the Holley carbs (required by rules) but they use custom sheet metal intakes. Those engines wind to the moon and make a ton of power. So it isn't the carbs, it is the manifold. And the manifold is just fine for street use.

Lots of good info!!!

I wonder what involves the "deep porting" of a stock six pack intake manifold?

You could always try one of these. Fits under a 69 1/2 lift off hood!

fits under a Challenger TA hood also

Nick Wilson built my 493 stroker with ported SR's, 12:1 compression, roller cam, and Hughes did a stage 2 porting on my manifold. On the dyno it made 734 HP at 6950 rpm so seems like the manifold is flowing well.

This..^^^^, in a big way Iagree. The small block intake has tall stands for the carbs and creates a deep deep long drop to the bottom plane. There's sharp turns there. Also, you can see how the #1 cylinder runner is kind of a up and down slope runner, to low IMO.

Like Andy said, it is a dual plane. That itself is a limitation. Excellent for the street, street strip car. Also know that the old Direct Connection carbs flowed more than the OEM set did/does.

Want.... Neeeed ...... Want ..... Neeeeeeed .... Want ... Drool on cool wacko factor...

LMAO

All six packs require a basic "set up" even stock.
The variable in the set up is only the jetting on the center carb. Once the base line is set and the car tuned, the jetting is adjusted if necessary and then the 2ndary springs are changed if required. Get the 6 pk tuning guide & use it.

As for the rest of you bad mouthing the intakes because the peak the peak hp blah blah blah - this is not the race section and no one has 690 hp engines.

Some of us have had great success making great hp & torque with six paks on small and big block stokers. 416/505 Since you six pak peak hp, poorly designed manifold guys never got a ride in any of our rocket ships you don't know what you missed.

Any stoker street engine loves a six pak - it's like an unlimited shot of nitrous.

I didn't notice any loss in top end and did gain a little low and mid range on my 400 hp 365" SB. I'm using a deep port matched mopar intake with the DC mechanical 6 pack. I can actually flat out floor it and open all 6 barrels at once and it goes like it was shoot out of a canon !! It does have a 4,400 rpm stall with drag radials. Plus the WOW factor over the single 4 bbl is worth it IMHO.

Where do I get the 6 pack tuning guide?

ask Cab...
I'd say they'd work just fine. You will have to adjust them but you'd have to adjust any carb you'd use.

IM THINKING ABOUT GETTING ONE OF THOSE LM1s

trying to adjust carbs without anything like that is just pure guesswork....or LOTS OF WORK AND TIME ....reading sparkplugs and stuff....which I dont really have time for...

I just wanna be sure Im starting with a good baseline and then tuning from there....

I will start with stock jetted and setup carbs. then go from there.

I think those LM1s are no longer available, and now there is a new version out.....but I heard abhout people saying that their new version is no good?

I just can't get my carbs running will always too too too rich.
My kingdom for Any help

have you checked the float levels? What springs? Is it from the primary or outboards? When I 1st set up my 1st 6-pack I unhooked the outboards. I adjusted the primary like any other crab, then messed around with the springs and things. What jets are you running? squiters?

What carbs are you using and what condition are they in?

This manifold is a lot less difficult to make work (and make the same power and torque) as the Weiand and offers more hood clearance.
Back in the mid 70’s Chrysler ran them both on the Keith Black dyno and we’re very close close in power. Politics ended up making the Weiand the manifold of choice on the few factory cars in SS.