The Ford Barn - View Single Post - Holley ECG-5 2110 on Stock '51 239?

scooder · 04-28-2016, 01:27 PM

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Is the carb you mention with the 1 1/16" venturis the one with the huge throttle plates?
If so you'd need to swap to a Merc four bolt manifold and bore the risers out to fit that carb. If you don't, it'll be a waste of time, and probably hurt the flow, even though the carb is bigger. This is due to the miss match in sizes between the carb base and manifold. The Merc one is the only one that'll bore out big enough, Ford ones you'd hit daylight and exhaust. Oddly the Merc one also needs boring out to match the size of the throttle plates that it actually came with from the factory.
Keep the jets stock for the carb, I mean use the 57's it came with, they will be damn close to perfect, 51's from an 8BA carb are way too small for that Big carb.
Just a note on "mathematically" working out required cfm. It's mostly baloney in the real world. Always spits out a cfm "need" that's to small. If it was right, fitting two carbs to a flathead would deliver less power, bad driveability and awful mpg. Which of course is nonsense if there set up correctly!! Just look at Walt's ride with four 97's on it with straight linkage!
And, the cfm numbers quoted for 94 family and 97 family carbs, are tested at 1.5" depression. Two barrel carbs should be tested at 3", four barrels are tested at 1.5". So before you even get to the math, the numbers are wrong.
Not quite so straight forward is it. Essentially, yes you can fit the bigger carb, with the relevant manifold and mods. It will be better, everywhere I'd guess, as the stock carb is very small for the engine. By how much? A bit. Would you feel it? Depends how sensitive your butt is. I can tell you going from one correctly functioning carb and ignition to a dual with correctly functioning carbs and ignition is very noticeable by my butt. Including better mpg, when I wasn't standing on the throttle at every chance.
If you've got the carb and manifold (bored out) give it a go. It's only nuts and bolts, I can easily come off again.
Martin.

04-28-2016, 01:27 PM	#6
scooder Senior Member Join Date: Jul 2010 Posts: 2,595	Re: Holley ECG-5 2110 on Stock '51 239? Sponsored Links (Register now to hide all advertisements) Is the carb you mention with the 1 1/16" venturis the one with the huge throttle plates? If so you'd need to swap to a Merc four bolt manifold and bore the risers out to fit that carb. If you don't, it'll be a waste of time, and probably hurt the flow, even though the carb is bigger. This is due to the miss match in sizes between the carb base and manifold. The Merc one is the only one that'll bore out big enough, Ford ones you'd hit daylight and exhaust. Oddly the Merc one also needs boring out to match the size of the throttle plates that it actually came with from the factory. Keep the jets stock for the carb, I mean use the 57's it came with, they will be damn close to perfect, 51's from an 8BA carb are way too small for that Big carb. Just a note on "mathematically" working out required cfm. It's mostly baloney in the real world. Always spits out a cfm "need" that's to small. If it was right, fitting two carbs to a flathead would deliver less power, bad driveability and awful mpg. Which of course is nonsense if there set up correctly!! Just look at Walt's ride with four 97's on it with straight linkage! And, the cfm numbers quoted for 94 family and 97 family carbs, are tested at 1.5" depression. Two barrel carbs should be tested at 3", four barrels are tested at 1.5". So before you even get to the math, the numbers are wrong. Not quite so straight forward is it. Essentially, yes you can fit the bigger carb, with the relevant manifold and mods. It will be better, everywhere I'd guess, as the stock carb is very small for the engine. By how much? A bit. Would you feel it? Depends how sensitive your butt is. I can tell you going from one correctly functioning carb and ignition to a dual with correctly functioning carbs and ignition is very noticeable by my butt. Including better mpg, when I wasn't standing on the throttle at every chance. If you've got the carb and manifold (bored out) give it a go. It's only nuts and bolts, I can easily come off again. Martin.