If a double pumper is good

[68 HEMI GTS]

Then a triple pumper must be better...

 

[PurpleBeeper]

Maybe on one of your track cars. I'd be interested to see if it got you off the line any faster and/or washed your rings.

 

[Budnicks]

If set up properly, look like the old Ford tri-power {406 or 427} style carbs
are they all 350cfm ?? or 500cfm ??
Maybe check out what they use to do with them,
to make them work properly on the drag-strip

if you have a high stall converter you probably won't be
activating the accel. pump discharge nozzles/squirteres much anyway
unless your at very light throttle than hammer the peddle to give a
bit more accel. pump shot

most combo's will do fine with a vacuum secondaries/outboards
I've had both styles literally no et improvement on a STR 14 or 15
with all 3 500cfm carbs & accel. pumps on all 3 carbs
vs the org. 350cfm AP with a 50cc conversion inboard & 500 cfm outboards vac./sec

from like 1979 Edelbrock STR with the vac. outboards,
sorry I can't find the photos of the mechanical carbs
it was a manual trans car at 1st too,
later tried them both wit an auto also,
no noticeable ET or MPH improvements...

my current 6bbl, still tinkering

Now with a manual transmission it may come into play more off
& on the throttle shifting or part throttle launches & then wooding it...

Street driving you'll hear the throttle more on the outboards
when you stomp it, it may not go any faster if you can't use the
extra shot/charge of full...

99% of people would be better off with a vacuum actuated secondaries
with the proper springs & a 350cfm inboard carbs too....
Only get the fuel when it is "actually needed" that way,
not when you foot says so, road course stuff it maybe an advantage some,
a bit of squirter/fuel discharge out of a corner, from part throttle...
I don't know really, I really didn't mess with it that much, way back when...

David Vizard's book "Super Tune & Modify Holley Carbs"
kind of meddles with it some,
so does the Larry Shepard "Mopar Six Pack Engine Handbook"
messed with it too IIRC

Good luck I'll be interested in if it does better for you than it did for me,
But IMO your current 6bbl set-up is pretty dialed in...

keep us posted

 

[440+6]

Yes!

 

[68 HEMI GTS]

There the 4782/83 Direct connection carbs. The outboards are basically the second halfs of 850 double pumpers. Im doubting I will use that little center carb. After talking with my dad we may try to do a big center (500cfm) using the mechanical outboards. I know it probably won't make much if any difference with the auto. I'm planning for going back to a clutch though in the future.

I've read these outboards do flow slightly better than vacuum carbs do to the throttle shaft.

 

[Budnicks]

There the 4782/83 Direct connection carbs. The outboards are basically the second halfs of 850 double pumpers. Im doubting I will use that little center carb. After talking with my dad we may try to do a big center (500cfm) using the mechanical outboards. I know it probably won't make much if any difference with the auto. I'm planning for going back to a clutch though in the future.

I've read these outboards do flow slightly better than vacuum carbs do to the throttle shaft.

Yeah the vacuum carbs "allegedly flow less" the OE stock stuff was rated at 940cfm total IIRC
a bigger center-carb won't do much either, other than cfm/flow volume once the outboards are open...

More mods to the engine below, it may help to go bigger...

I think IIRC had the same Direct Connection Carbs too,
it was a long time ago, my memory about specific #'s
"is not really good sometimes"

My center 350cfm I have now flows well over 455cfm,
{with no 500cfm base plate, still 350cfm}
just changing butterfly bolts {flatter ones}, every little bit helps
knife edging the leading edge of butterfly's will increase it more too
among many other polishing & venturi tricks etc.

---------------------------------------------------------------------

Changing to a 500cfm 2300 base plate too
{like the ones they use in some NASCAR classes}, may help,
I've had better luck with the 350cfm thou..

here are 2 of the Holley 2300 500cfm Throttle body base plate
I don't remember which is what or better etc.
Click on the photos it will have the part #'s

not sure but IIRC some minor mods
had to be made for 6bbl linkage stuff

bottom one was for vacuum stuff IIRC

Good luck, have fun keep us posted

 

[oldbee]

AND I clicked this thread thinking it was a takeoff of "ski's" one-liners!!!!!!my bad.

 

[66Satellite47]

Well I ran a 6 pak with a 500 cfm center carb, I did modify it to a vacumn setup. It worked very well, when I worked the spring set ups & the jet sets.

 

[68 HEMI GTS]

Well I ran a 6 pak with a 500 cfm center carb, I did modify it to a vacumn setup. It worked very well, when I worked the spring set ups & the jet sets.

I run a 500 with the vacuum outboards. Works well as the time slips are proof of that.

 

[Cranky]

Ran two 750 TR carbs on a Weiand TR intake and didn't have any wash but it wasn't street driven either. With a 4500 stall, the car would run a 10.69 leaving at an idle and stalling it up it ran a 10.68. The car would run high 10.50's with cool weather and tuned up but it wasn't consistent. I liked being able to go to the track and know it would run the same numbers with it not tuned to go as fast as it could....

 

[68 HEMI GTS]

Maybe on one of your track cars. I'd be interested to see if it got you off the line any faster and/or washed your rings.

No concern of washing out rings. Holleys are infanetly tunable, espically if I break out my drills and taps..

 

[66Satellite47]

My experience with drill bits on the end carb plates was not good. Finally went back to new stock plates. Car ran great after that. Later talked to a carb pro that explained the best method was to use reamers not drill bits. I presume he was right.

 

[66Satellite47]

I should have said I had 3 sets of 6 Pak carbs. The first was the one with the 500 center carb that I modified for vacumn to end carbs. Then I had a stock '70 setup & a '71 setup. The '70 setup with nearly stock jets & jet plates worked really well. I did modify the accel pump & squirter a bit. I went up 2 numbers in the center carb & a slight increase in the end carb plates. All was with the '69 aluminum manifold.

 

[lewtot184]

i ran a set of those carbs back in the day. very easy to tune and would work fine in a properly set-up drag car. to my knowledge no aftermarket linkage was ever produced, i fabbed my own. edelbrock did offer the pivots for the throttle arms for a while but seriously doubt they do anymore. any carb can "wash" the rings if it can't control fuel flow.

 

[moparpoor]

I'm a big fan of the mechanical setup. Been looking for a set myself. They were on grandpas a12 bee. The car would idle like a 318 and throttle response any where was flawless.

 

[68 HEMI GTS]

Float bowls were a bit rough. Wasn't much finish left by the time I got it clean, So I resorted to powder coating.

 

[69 GTX]

looks nice

 

[68 HEMI GTS]

I've been working on them here and there. Gonna start with the small center for now. If I find a good buy on a 4412 (500cfm) I'll plug it in the center.

 

[Budnicks]

Looks great

let us know how well it works out,
all your tricks etc.

 

[68 HEMI GTS]

Looks great

let us know how well it works out,
all your tricks etc.

Thanks and will do. No real tricks yet, I built them pretty much stock other than jetting and acc pump cams and squirters. I'll get a base line and go from there. Depending on how they idle and such I may convert them to 6 corner