Inliners International Forums General Discussion Engines Probably a crazy carb question

OK....sometimes when I think too much I get goofy ideas. Here is what I was wondering.

Seems like the cheapest 4bbls to lay hands on are 600 CFM Holleys because they are all over the place. For a street driven Chevy 230, this is obviously WAY more than is needed. A lot of guys talk about the 32/36 Weber as a replacement for the Rochester 1bbls, but I was wondering......

What if you took a typical vacuum secondary 600 CFM Holley and plugged the necessary jets/passages to a allow only one primary and one secondary barrel to function. Remove the throttle plates and seal the lower bores of the deactivated barrels.

Couldn't this give a better "progressive" 2bbl when compared to the Weber? Certainly the tuning parts would be easier to find and I think the overall flow would be better when you do need top end.

Obviously this is an idea only for those of us that have no illusions of performance, but just want a good daily driver with decent MPG.

This might even allow you to make use of a partially damaged Holley that would be unusable as a 4bbl. Isn't that a "green" idea? Holley recycling!

OK all.....what do you think? Is this the dumbest idea ever....or do you think it might have merit? Anyone ever try anything like this before?

Kirk

The Webber will work better.
Hollys are not known for mileage.

Better off running a Webber for mileage.
Nice try though.

MBHD

What is the second name on a weber?
As far as the conversion on a four barrel you will never know until you try it. You may have stumbled on the worlds greatest idea or the worlds worst idea, but if you try it you will gain a lot of knowledge along the way. If no one ever tried a new idea we would all be driving vehicles with up draft carbs and gravity flow fuel systems. In fact we woulb still be walking or riding horses.

K5

Yes, you are thinking way too much about. A 4 barrell carb is designed to operate effiently as a 4 barrel. When you start fiddeling with a piece of well engineered carb likw a Holley you run the chance of it flooding or starving your motor with likely disasterous effects.

Stick to a 2 barrell or High output 1 barrell carb if you want efficent power and mileage.

RapRap
1940 ChoppedChevyCoupe

Maybe I'm just very agreeable but I agree with all 3 replies:
1. The Weber is a super little carb, I used to collect them like lug nuts back in the day, great MPG and very tunable too.
And, any place I've run a Holley, I've always seen another carb get better MPG on that same car - Rochester, Autolite, etc.
2. On the other hand, it is true the 600 Holley is everywhere, this would be a good experiment.
3. At first I didn't agree with the comment about the "designed as a 4 barrel" but then thought it through. Here is the part that might be tricky:
You could block off the throttle plates and fuel and air and idle fuel circuits on one side, fine.
Now you have a progressive 2-barrel. I see no other issues except one:
When will the secondary open?
As I recall it's the choke side of the carb that sends the signal to open the secondary, and sometimes there is a signal hole in BOTH the primary and secondary venturi. THESE are in fact designed to open BOTH secondaries, when they decide that BOTH primaries are overextended. Would these same signals open the secondary properly with the throttle side blocked off?
Maybe, maybe not.
I see no harm in trying it, the secondary will either not open soon enough or bog from opening too soon.
In a light car with steep gears you could probably even get away with connecting the secondary mechanically and hope it doesn't bog from lack of pump shot.
Hey, go for it and let us know!