Replacing 2 barrel w/4 barrel question

[elektrik]

Ok, so I'm at Oreilly's auto the other day picking up a brake drum, and I happen to mention to another customer who was admiring my truck (I call them "fan of the day" cause I get at least 1 comment a day ) and the guy behind the counter says "you should convert to a 4 barrel" and I'm like "no thanks, I want to still get some decent gas mileage". So he says "you'll get better gas mileage with a 4 barrel." I'm like "why would you say that?" He says "because the ports at the bottom of a 4 barrel are smaller than the 2 barrel, since there's more" - implying that because the ports are smaller, it would use less gas.

...Now I'm not a mechanic, I only play one on TV (ok, I don't even play one on TV), but that seemed a little far fetched to me. Could some of the more learned people let me know if what he was saying is true or am I correct in thinking he's blowing smoke out of his hind parts?

[Longhorn Man]

there is a huge catch with that comment.
He is assuming you can keep your foot feather light and not open the secondarys. Assuming you can do that, he is 100% right.

[Mordachai]

vacuum secondaries are the best thing since sliced bread...

[Wrenchbender Ret]

It only applies if you use a spead bore type carb like a Quadrajet. They have very small primary bores. You get good fuel mixture. But like the guys say when you put your foot in it you open the secondarys & they are huge.

[WorkinLonghorn]

The theories above sound correct,however I have noticed in 2 different 1969 trucks both with 350 engines and 4 brl carbs that if I keep my foot completely out of it for an entire tank of gas I get 11-12 MPH. Then for the next tank I'll have multiple massive loads of dirt and rock all the way up into the hills of Pasadena. Mileage; 11-12 MPG. The next tank I'll say screw it,I'm going to have fun,and act like an idiot and race anybody and everybody that wants to mess with me. And after all of this I notice that my mileage is roughly....................11-12 MPH. Always.
I've talked to other guys at the dump with similar trucks and similar stories.
So I don't know what mileage you're getting now,but you might as well have the 4 barrel. You only live once they say.

[Mordachai]

that's a great point , because I have a holley 2-barrel and I get from 12-15mpg, pretty much all the time. Just like you, foot deep in the gas, or barely idling along, I get the same 12-15 mpg.
Every once in a while I take it for longer rides, with no stoplights, and on those type runs, keeping it at about 45 I get some 18-20 mpg. But that's at a steady slow cruise, no stop and go....

[elektrik]

Originally Posted by Mordachai

that's a great point , because I have a holley 2-barrel and I get from 12-15mpg, pretty much all the time. Just like you, foot deep in the gas, or barely idling along, I get the same 12-15 mpg.
Every once in a while I take it for longer rides, with no stoplights, and on those type runs, keeping it at about 45 I get some 18-20 mpg. But that's at a steady slow cruise, no stop and go....

See now, I'm getting around 12.5 - 13 mpg with the 2 barrel. It has plenty power for me (I don't get on her much), so I'm finding it hard to justify the switch over,especially if what Longhorn Man says is true...

Thanks for enlightening me guys.

[WorkinLonghorn]

Mordachai says;

keeping it at about 45 I get some 18-20 mpg.

WOW! if I ever got 18-20 I'd throw a block party with a live band,belly-dancers, free beer,the works!

[Wrenchbender Ret]

Leaving it alone is a very wise decision. with All the hassle & expense of changing it over it would take years to make it up with a tiny increase in mileage.

[boundstaffpress]

It's like buying a transmission to improve gas milage. The improvement will not pay for itself.
I like driving a well-tuned quadrajet - economy when I drive like a grandma, and power when I want to smoke some young buck. But I love my hassle-free two barrel with manual choke on my 67.

[elektrik]

Originally Posted by boundstaffpress

It's like buying a transmission to improve gas milage. The improvement will not pay for itself.

That's pretty much what I figured...and (offtopic)why the heck does your pic look so familiar??

[streetstar]

Originally Posted by elektrik

That's pretty much what I figured...and (offtopic)why the heck does your pic look so familiar??

its the guy from the tv show "mythbusters"

---- i haven't driven a 2 barrel vehicle in 20 years, until i picked up a 69 a week ago that still had the 307/2 barrell.

I know i am easily amused, but i have to admit to being pretty stoked about the power it still has -- it will definitely move out (but its not a barn burner, and my big block truck would trounce it, but its a match for my K5 with a 350 tbi, power wise)

Mine's staying a 2 barrel, -- its my excuse to drive around like a farmer on his way to town on Sunday

[elektrik]

Originally Posted by streetstar

its the guy from the tv show "mythbusters"

---- i haven't driven a 2 barrel vehicle in 20 years, until i picked up a 69 a week ago that still had the 307/2 barrell.

I know i am easily amused, but i have to admit to being pretty stoked about the power it still has -- it will definitely move out (but its not a barn burner, and my big block truck would trounce it, but its a match for my K5 with a 350 tbi, power wise)

Mine's staying a 2 barrel, -- its my excuse to drive around like a farmer on his way to town on Sunday

Thanks for letting me know why the pic's familiar-I'll even excuse the inadvertant vague association of myself with a farmer on his way to town on Sunday

BTW, Barrel has 1 "L"