400/451 6 pack...what draw backs can you guys see?

[AKcharger]

Good day and thanks for reading this...

I've decided to take my wife's '72 and go with the 440 source 451 kit along with a 6 pack. I know pound for pound a good 4 bbl will out perform it but I got a raise at work. Reason I'm looking at the 6 pack is simple...nothing looks cooler when you pop the hood then a 6 pack set up (no offense to our hemi friends)
Objective is a nice street car, runs well, dependable and I would like to see somewhere in the 13 sec range if I ran it in the 1/4 mile

Now the question is what if any draw backs are there? I've heard stories about being hard to tune, finicky ect, but does anyone have any experience with them? feed back welcome.

Thanks

- 440 source® 451 kit... balanced
- Engle K56 cam or equivalent
- 452 heads
- compression 9.5-1
- Stock HP Cast iron manifolds with H-pipe
- 3.91 gear
- Oh, my block is cast #3614230-4...I heard that was the "good one?"

[hemihead]

If you don't know anything about tuning or carbs you will be disappointed.

[Ghoste]

Of course, it could also be seen as an excellent challenge to make yourself learn it. 

[AKcharger]

Well I can adjust mixture and idle...do you have to mess with floats much?

[daytonalo]

No offense, Mopar is coming out with six pac shortly for Hemi ! For me , nothing like 8 barrel

[Charger1973]

Well I can adjust mixture and idle...do you have to mess with floats much?

I asked the same question to a guy a couple weeks ago.  Hes the original owner of a 50,000 mile 69 Superbee 440+6 4 speed.  He said that when the car was new, it was a little fussy.  He said its extremely easy to adjust as long as you dont mess with the floats ect.  He said after a while the motor got broken in and its run great with minimal tuning necessary.  Just the mixture/idle settings.  I was glad to hear that, gives me hope of one day adding a 6 pack to mine as well.   

[AKcharger]

Thanks Sir...I plan to "interview" some people at Carlisle who own 6 packs, hope I can find people who work on them. I discovered just because people OWN a muscle car doesn't mean they work on it or restored 'em.

I think an entire set-up goes for $2100 for a B-engine

[Ghoste]

That's been the truth since the day they were new.

[firefighter3931]

Ak,

Keeping the build mild will make carb tuning easier. The problem with 6-packs is that the fuel curve isn't really designed for cam profiles with lots of overlap & duration. The K56 would be a nice match for a 6-pack induction setup in the 451 you're contemplating. A wider LSA on the cam will help mellow it out and reduce overlap which helps with HP exhaust manifolds and 6-pack tuning. 



Ron

[AKcharger]

LSA  is that an adjustment or is it built into the cam?

[Challenger340]

pm sent.

[471_Magnum]

I agree with Firefighter and Hemihead.

Out of the box on a very mild (ie STOCK) motor, a Six Pack set-up will run fine, but you will need to do some tuning on a souped up motor with some cam.

Stock Six Pack outboard carbs have metering plates, not blocks with jets, so they need to be convertered. All the same principles apply as tuning a 4 barrel, but everything is harder to get at with the Six Pack. Pretty much have to pull the carbs to get at anything. It's just a real PITA. Not something a novice carb tuner would want to tackle.

[70sixpkrt]

A good thing to do is use Promax's outboard billet base. The mixture screws are at an angle so it's easy to get to. I would also use their jettable  plates for the outboards and the metering plate for the center carb. http://promaxcarbs.bizland.com/Sixhome.chtml

[AKcharger]

Thanks Sir...just sent 'em an e-mail

[70sixpkrt]

You only need 1 outboard billet base for the rear carb. You still can get to the front carb.

[AKcharger]

Thanks Sir

I called 'em and talked to Brad? he said they had the biullet bases to adjust mixture without removing the carbs( you had to remove cards to adjust mixture? Good ol' Carters!)

Anyway he said they also have a service to run the setup across a dyno to adjust everything...I LOVE that idea so I'm going with that around Sept.

Thanks 70 6 pk!

[70sixpkrt]

No problem. Actually they are Holley carbs. I am running the billet base for the rear carb, their metering plate for the center carb, and the jettable plates in both outboards and love all of them.

[AKcharger]

Sorry sir, wasn't clear...with Carters (and now edelbrock knock offs) you can adjust mixture/floats without removing the carb...you can even cange jets with the carb still installed