Six Shooter vs. Six Pack

[Sweet5ltr]

Is their a large difference in carburetor performance? The BGs state they each flow 250cfm (750cfm total, in comparison to 1350cfm), but I have always been under the impression that BG flow numbers are always on the low side. I can purchase a six shooter kit from someone for a $1,000 and it's complete, with everything I would need to install to convert over to a six pack. I would like a holley setup, but I am looking at $500+ in additional items to get it right; linkage, building an air cleaner, fab work for brackets, etc. The six shooter kit looks very straight forward, and is already ready to bolt on with less than 1,500 miles. I am installing it on a vintage DC super stock weiand cross ram, if that makes a difference. I am not after every last HP, but don't want to be held back considerably. Just a 451 with ported iron heads, 10:1CR, and a .509 MP Cam. I have a very well matched intake and proform/holley DP carburetor right now, so I am not looking for a performance increase just a six pack setup for the cruise in's. I have the funds for either build, but would rather spend the cash that I could save on other items. Thanks!

 

[lewtot184]

the 6 shooter carbs are quite a bit smaller than the factory carbs. don't get lost in the cfm game, sometimes its bogus. the factory center carb has 1 3/16" venturis and 1 1/2' throttle bores; secondary carbs have 1 9/16" venturi and 1 3/4" throttle bores. the 6 shooter is 1 3/16" venturi, and 1 1/2" throttle bores on all 3 carbs, probably fine for a 340 and under. the larger engine will prefer the big factory carbs. the true rating of the factory carbs is 1030cfm.

 

[5.7 hemi]

The factory carbs dont have the tuning ability as the bg carbs.

 

[lewtot184]

The factory carbs dont have the tuning ability as the bg carbs.

where did you get this information? do you run 6-paks?

 

[Supershafts]

I do and the BG set up is a easier tuning option, it might not have the cfm and most people don't need the cfm capabilities of the real 6pk, but have you ever tuned carbs on a real 6pk? compared to the BG it's better . . . tuning 6paks involves work and modifying plates.
Unless you use aftermarket plates which helps some with making some tuning changes.

 

[Sweet5ltr]

the 6 shooter carbs are quite a bit smaller than the factory carbs. don't get lost in the cfm game, sometimes its bogus. the factory center carb has 1 3/16" venturis and 1 1/2' throttle bores; secondary carbs have 1 9/16" venturi and 1 3/4" throttle bores. the 6 shooter is 1 3/16" venturi, and 1 1/2" throttle bores on all 3 carbs, probably fine for a 340 and under. the larger engine will prefer the big factory carbs. the true rating of the factory carbs is 1030cfm.

So could we say that the 250CFM rating on the BG carb is similar to the 350CFM rating on the Holley Carburetor?

 

[lewtot184]

I do and the BG set up is a easier tuning option, it might not have the cfm and most people don't need the cfm capabilities of the real 6pk, but have you ever tuned carbs on a real 6pk? compared to the BG it's better . . . tuning 6paks involves work and modifying plates.
Unless you use aftermarket plates which helps some with making some tuning changes.

i've been running 6-paks since 1970. i have quite a bit of experience with the factory carbs. most of the stuff on the internet about factory 6-paks is unfounded heresay.

 

[lewtot184]

So could we say that the 250CFM rating on the BG carb is similar to the 350CFM rating on the Holley Carburetor?

the holley 350cfm rating was taken at 3"hg, the bg 250cfm rating was taken at 1.5"hg. long story short, they're the same.

 

[lewtot184]

my current driver.

 

[Supershafts]

i've been running 6-paks since 1970. i have quite a bit of experience with the factory carbs. most of the stuff on the internet about factory 6-paks is unfounded heresay.

Well then you know tuning them isn't like that of the BG set up, making the tuning easier, and until the other plates came around drill bits were part of the tools

 

[Sweet5ltr]

My father had an original six pack setup off a 340 (swapped intake manifolds at Chrysler dealer) on a 63' Dodge with a 383, back when you could scour your local pull-a-part and find quality items. We aren't too worried about the tuning aspects, but I could see how the Barry Grants would give us more options to fine tune with the weiand cross ram. The Barry Grant setup is all their, and ready to bolt on and looks great and would save me at the minimum $500-700. I'll let everyone know what we go with, and hopefully it's sooner than later! Thanks for all the input.

 

[lewtot184]

Well then you know tuning them isn't like that of the BG set up, making the tuning easier, and until the other plates came around drill bits were part of the tools

maybe in your world but not mine.

 

[5.7 hemi]

It's the plates. They have an idle circuit on the bg stuff that the factory doesn't have if memory serves correct. Plus you can get aftermarket plates that allow the same tuning for the factory stuff. Mopar magazine did a article on this some few years back and it was quite simple to do.

 

[lewtot184]

It's the plates. They have an idle circuit on the bg stuff that the factory doesn't have if memory serves correct. Plus you can get aftermarket plates that allow the same tuning for the factory stuff. Mopar magazine did a article on this some few years back and it was quite simple to do.

factory carbs have an adjustable idle circut on all 6 venturis. actuall all carbs have an idle circut on all venturis but some aren't adjustable. if your referring to the aftermarket secondary metering plates that will take screw in jets i don't use them or the throttle plates with the angled mixture screws. i just never felt the need and doubt their necessity; but some people feel comfortable spending money for those things.

 

[5.7 hemi]

That could be it, I'm going off memory.

 

[Meep-Meep]

One thing to consider with all carbs is they are more than just CFM and jets. Emulsion tubes play a huge roll in providing the correct mixture at different areas in the RPM range. Also, old carbs are calibrated for gas we no longer have at the pump, and that's another thing to consider in my opinion. Since BG is a fairly recent company it may be safe to assume they did all their R&D with current gas, but that theory should be verified. For the old six pack carbs getting the new primary metering block may be the best investment you can make.

A comment abut your intake - assuming you are planning on running the Weiand six pack tunnel ram. That intake plenum required extensive modifications in order to provide equal fuel distribution to all cylinders, but again, that was with old gas, which I'm sure had different vapor characteristics when exposed to an elevated temperature. The carbs that sat on top also were heavily modified with stagger jetting and different air bleed sizes.

The true CFM rating of the factory six pack carbs is right about 800 CFM in total, and all that sits on a divided plenum intake, which helps provide a stronger signal to the carbs.

I'd go with the more modern, and in your case, cheaper, BG carbs and be prepared to do a lot of tuning. A visit to a chassis dyno that can hook up EGT sensors to each header tube is golden. Back in the 80's I grabbed a small thermocouple gauge and inserted the junction into a 1/16" hole I drilled in my header tube (right near the flange) so it can pick up the exhaust gas stream for the most accurate and instantaneous reading. It was my thinking that measuring the outside of the header tube was just that and not a true representation of what is going on with the combustion process.

 

[Supershafts]

maybe in your world but not mine.

Well then you must be using stock stuff with stock power..

Otherwise you would know modifying the plates on the outboard carbs and then going to the aftermarket plates when they came out to make things somewhat easier, along with other modifications.
saying there was no need for this type of stuff, maybe if you want to drive to the parking lot and open your hood, then yes

The mixture screws unless already previously modified aren't accessible.

So the bg stuff is easier to tune.

 

[lewtot184]

Well then you must be using stock stuff with stock power..

Otherwise you would know modifying the plates on the outboard carbs and then going to the aftermarket plates when they came out to make things somewhat easier, along with other modifications.
saying there was no need for this type of stuff, maybe if you want to drive to the parking lot and open your hood, then yes

The mixture screws unless already previously modified aren't accessible.

So the bg stuff is easier to tune.

:icon_thumbdown:

 

[kdtjb]

I thought BG went broke?

 

[Supershafts]

The part of BG known as Demon did