New 6 bbl, what are the best upgrades

Lionized · Mar 28, 2015

mac said:
is that a 500 cfm center carb?

Looks like all one carb to me.

Bigal75 · Mar 28, 2015

The outboard carbs open mechanically?

66Satellite47 · Mar 28, 2015

mac said:
is that a 500 cfm center carb?

Very interesting. The first six pack I bought in '74 (from '69 1/2 car w/ alum manifold & air cleaner) had a 500 2 bbl cut to fit in the center . Had mechanical linkage like any good bowtie boy would do. I drilled in a vacum port, converted back to vac secondaries. Made the mistake of following the DC "drilling" instructions. Didn't work well for me. The thing would miss in top of 2nd gear & all through high. Chased the ignition for months. Noticed TINY swirl marks left by the drill bit in the end carb jet plates. Bought stock sized jet plates, problem solved. Ran great with stock end carb jetting & richened the end carb idle mixture screws.

68 HEMI GTS · Mar 28, 2015

mac said:
is that a 500 cfm center carb?

yes, my dad does the conversions. he's somewhat of a Holley tuning guru in the area. i just try to pick up as much as i can from him. wish osmosis worked...

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Bigal75 said:
The outboard carbs open mechanically?

nope, there set up to work off a vacuum single just like the stock center carb. we tune with the secondary springs, and sometimes he re-calibrates the kill bleeds depending on the combo.

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Phil McGrath said:
Its started as a six-pack and its still every bit a six-pack, but one needs too look past the braided steel fuel lines and the removal of the air horn choke tower and not be distracted. Its right out in the open for all too see its that sneeky, you have too look real hard but its there right out in the open none the less....... That's all I will say until the owner comes clean if he so choose too do so, I will respect his covert shenanigans..... If he has the Mopar faithful this stumped the Bowtie brigade are surly to be clueless.

I bet it pulls at the midrange and has a top end charge unlike any other six-pack on the road, that's the only hint I will give.

its amazing how much better the bigger center carb works. pretty much from idle right on up. you really can tell the difference when your tooling around town just using the 2 barrel, there's way more torque than the small center carb. and yea, most people even so called proclaimed carb experts, mopar experts, and whom ever else never even notice it. pretty cool mod. it would be interesting sometime to do a back to back at the track, but usually once you drive it with the big center carb the thought of putting the factory one back on will never cross your mind again. we've done this on a few different 440's and are never disappointed. maybe in the next few years i'll try my upper end on a 500ci motor. wouldn't mind running 10's on a pump gas street motor that still gets six pack mileage...

to date (only 2nd time to the track) i've been 11.58 @ 116 with a sketchy convertor that i sent out this winter. that was also through mufflers driving to the track, and only pulling a 1.7 60ft spinning on drag radials. with the convertor straightened out on slicks i expect a little more. uncorked she may even run better. i figure with me its at least 4000lbs, its a legitimate street car. everything works. it even gets driven to work. and this is a very basic, not quite ideal 440 short block. it just has good heads and good tuning.

Phil McGrath · Mar 29, 2015

68 HEMI GTS said:
yes, my dad does the conversions. he's somewhat of a Holley tuning guru in the area. i just try to pick up as much as i can from him. Its amazing how much better the bigger center carb works. pretty much from idle right on up. you really can tell the difference when your tooling around town just using the 2 barrel, there's way more torque than the small center carb. and yea, most people even so called proclaimed carb experts, mopar experts, and whom ever else never even notice it. pretty cool mod. it would be interesting sometime to do a back to back at the track, but usually once you drive it with the big center carb the thought of putting the factory one back on will never cross your mind again. we've done this on a few different 440's and are never disappointed. maybe in the next few years i'll try my upper end on a 500ci motor. wouldn't mind running 10's on a pump gas street motor that still gets six pack mileage...

to date (only 2nd time to the track) i've been 11.58 @ 116 with a sketchy convertor that i sent out this winter. that was also through mufflers driving to the track (even idled through the MCD's drive through for breakfast that morning still about 20 min away from the track), and only pulling a 1.7 60ft spinning on drag radials. with the convertor straightened out on slicks i expect a little more. uncorked she may even run better. i figure with me its atleast 4000lbs, its a legitimate street car. everything works. it even gets driven to work. and this is a very basic, not quite ideal 440 short block. it just has good heads and good tuning.

if there's any interest in people wanting the 500 cfm carbs built let me know. im not sure where he stands or even if he cares to do any but, i know he would atleast need six pack throttle shafts supplied with the conversions along with a decent 500cfm core as a minimum.

I've seen a few outlaw circle track 4412's with flow ratings claimed of 750cfm witch I suspect is a weeee bit overrated, however I think 650+cfm is more realistic. My thinking is the larger center will allow the engine too get over the hump so when the outboards start too kick open the transition isn't so violent spin and blow off the tires or bog and stumble before it gets gathered back up again.

A nice Six Pack set up and a intake that's been flowed with a aim toward balanced flow and not just maxed out would work great on a hot 440 or 500 stroker, I wonder how much better that set up would work on the old Weiand IR intake.

rumblefish360 · Mar 29, 2015

Where is the power valve restriction channel?

Doing a 360/6

Phil McGrath · Mar 29, 2015

rumblefish360 said:
Where is the power valve restriction channel?

Doing a 360/6

It would be in the center carbs metering block, the picture posted are from the outboard metering plates. That may explain why you cant find the PVRC.

New 6 bbl, what are the best upgrades

Lionized

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Bigal75

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66Satellite47

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68 HEMI GTS

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Phil McGrath

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rumblefish360

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Phil McGrath

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