Gary's Carburetor Tests
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Gary's Carburetor Tests
 
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As many of you know, I recently built an Edelbrock 1406 for my brother's '55 Chevy. And, by "built" I mean I put together two different carbs as well as several new parts to make one functional, stock, 600 CFM carb. Further, I put it on Big Blue to test it in order to ensure that it won't quit him right in the middle of breaking in that new Performer cam. In fact, it performed (pun intended) well on Big Blue in place of the 750 CFM Performer carb that had been on there.
Someplace along the line David/1986F150Six suggested that I run a test on the two Edelbrocks as well as the 750 CFM Street Demon I have. And, his suggested test was to run the same route he and I did about 2 1/2 years ago with our 6 cylinder trucks. Further, he suggested that I do a full-throttle run from 30 to 70 MPH in top gear and time it. Well, today my brother called and wants his carb. So I did the first run on this route:  And the way I drove it was to average the speed limit. In other words, I let it pull down maybe 2 MPH on hills, of which there are plenty, and come up about the same on the downhill stretches. And the speed limit is 65 from Mr Bass, where I filled it to the brim, through Hominy and up and around to Barnsdall, and then 55 to Avant, although the speed limit drops to 25 to 35 in the towns. And from Avant south it is 50 MPH. So, how'd we do? Well, in spite of Google saying that route is 63.1 miles, Big Blue thinks it is 65.0 miles. And, I got 5.71 gallons in it after that, again to the brim, for an average of 11.384 MPG. (Yep, its a 460.) As for the 30-70 MPH run, that took 15.78 seconds, and I started at the east edge of the bridge over the lake - for my reference next time. I now have the Edelbrock 750 back on there, and will test it in the not too distant future. Then I'll swap the Street Demon on and go again.
Gary, AKA "Gary fellow": Profile
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
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Jonathan - I'll have to dig up the results that David and I got with the six cylinder trucks. Maybe he will know where they are.
As for the MPG this time, I was hoping for more. But we shall see what the other carbs get. I can say that the 1406 worked flawlessly. The choke could use a teeny bit more pre-load, but who knows how it'll work on the little 350, so I left it on the index. And the overall jetting gives a smooth experience. No bogs or lags anywhere, and you can't tell when the metering rods pop up nor when the secondaries open. Just a nice, smooth response. And, the engine pulls strongly. I forgot to say that there was a little more idling than one would expect in an MPG test. There are two places where there's construction, and in one case the road is down to one lane with a timed light. I was the first one to it yesterday, so turned Big Blue off to save gas. But, when the light turned green he wouldn't crank, and by the time I jumped out and jumpered the relay it was red again. So, I idled through the next cycle of maybe 4 minutes.  Also, I took a video of the idle RPM and vacuum with both carbs. After dialing in the air/fuel mix on both carbs and setting the RPM to be the same, the vacuum was essentially the same - which fits with my expectation. And, the average vacuum of 20" and a smidgen more tells me that the engine is in good shape and the cam is quite mild. But the 2" swing from 19 to 21 also tells me there are valve problems. However, none of this will really matter on the MPG runs as they'll all be with the same engine, tire pressure, etc. Basically the only variables I can think of are the air temp and the wind speed and direction.
Gary, AKA "Gary fellow": Profile
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
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Bill - Your 12.5 MPG is, as you said but for everyone else's understanding, with the E4OD's OD dropping the R's to 1776 @ 65 MPH. (That comes from our calculator [Driveline/Calculators], which confirms your RPM as 1503 @ 55 MPH). In comparison, Big Blue is running 2501 RPM @ 65 MPH. No wonder he's thirsty!
However, Big Blue's gearing allows him to pull hills almost as if they aren't there. Coming out of the little burg of Avant there's a REALLY steep hill, and you've been in a 25 MPH speed limit, which goes to 50 as the hill starts. I wondered if BB would pull it in 4th, but was blown away at how easily he did it.  I used an app called SpeedBox that recorded the speed and altitude each second of the trip. So, I should be able to figure out how steep the hill is from the data, but am headed out to meet my brother at the moment, so will check later. David - That's the report! Wow, Blue got 19.95 MPG and 'Lil Red got 21.69. Comparing Big Blue to Blue, there's no comparison. Blue tows so easily, and for the 2500 mile trip to Lake Powell and back running 65 MPH and towing the 25' Sea Ray we got 11.0 MPG. Running the A/C, listening to The 60's On 6, and frequently running the massaging seats. In absolute comfort. Jim says "Progress is good", and I'd say that's progress.
Gary, AKA "Gary fellow": Profile
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
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And Gary will repeat the test with the two other carburetors!
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Yep, it was the highlight of the day.
 And this reminds me that I need to do the route again with the 750 on Big Blue. And not turn him off at the light.
Gary, AKA "Gary fellow": Profile
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
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