I was reading the above article and saw that they used a Holley 94 two-barrel carburetor on a stock manifold, 261 engine. The article claims 7-10 more miles to the gallon.
Hmmm.
For you Carburetor experts. Is that true (ish).
Chris
Rock49 aka C-Rodg work in progress 1956 Chevy 3100 261 engine
just on the face of it that MPG increase claim is bogus. Even if it got 15 mpg prior to the carb swap, a 50% increase in mileage just isn't realistic.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
A Holley 94 is for a Ford flathead V8 239 cubic inch engine. I ran and rebuilt bunches of them when my daily driver was a 1947 Mercury convertible. They're good carburetors, but nothing fancy, and not much of an improvement, if any, over a Rochester B. The slightly bigger venturi Holley with the same 3-bolt footprint used on the 1955-57 Ford 272 overhead valve V8 engine would be a better choice for a 261 engine. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Klhansen, The 7-10 mpg increase sounded bogus to me but I don't know enough about carburetors to call it. So I thought I would ask.
Jerry, Thanks for the details.
As I understand it, from what I have read in th forum. A one barel carburetor either a Carter or Rochester is the way to go on a stock 235 for daily driving. Or am I missing something?
Also didn't the 261 come with a larger venturi Rochester? If so how would it compare to the 55-57 larger venturi Holley?
Rock49 aka C-Rodg work in progress 1956 Chevy 3100 261 engine
Yes, there was a slightly bigger Rochester carb on the 261. Like a lot of other 261 stuff, they're hard to find, and after 60-something years, anything you do locate will have been worn out and rebuilt, possibly more than once. If a 2-barrel carb of any kind is used with an original stovebolt intake manifold, an adapter must be used. That reduces the efficiency of the intake system pretty severely. It's possible to modify an intake to use a 2 barrel properly, but it's a complicated procedure involving machining and welding.
One option for the 261 would be to find a Carter YF carburetor for a 258 cubic inch AMC/Jeep inline six. It is a bolt-on swap to a stovebolt 1 barrel intake, with only a little tinkering with the fuel line routing and throttle linkage. It's also 30-something years' newer production. RUN- - - -do not walk away from the "new" carburetors that claim to be Carter YF clones- - - -they're made overseas and the quality control sucks like a vacuum cleaner! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
The Ford Holley 94 was designed for Ford's Load-O-Matic system that used vacuum advance only. No centrifugal advance. This has to be dealt with. 1956 Ford 272 was the last year for the Holley 94. GMC 302 used a variant of the the Holley 94 but it used only centrifugal advance. The Holley 94 from a 272 with the vacuum blocked off was was my carburetor of choice for 270 GMC. Back when I was younger I did a lot of playing around with Holley 94. 3 of them make a 302 GMC run.
