69 Pont, 2bbl to 4bbl, MPG questions

I've got a stock 69 Pont 2bbl 350. I found some deals on craigslist for a non EGR Edelbrock Performer manifold and a Edelbrock 500 CFM carb. Gaskets, brackets, all told it looks like I would spend 250 to convert. I get 16-17 MPG on the freeway right now with the stock 2bbl set up. Would converting improve my highway mileage?


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I seriously doubt changing to an Edelbrock 500 cfm 4-bbl carb and intake will improve the mileage.

The 2G Rochester your engine came with isn't the best carb for mileage, but being a 2-bbl it will obviously use less fuel when you accelerate hard than a 4-bbl. If you were to use a Rochester Dualjet (which is the primary side of a Q-jet), you might get a little better mileage- but there's no intake that will fit that carb to your engine. That leaves using a Q-jet 4-bbl carb. It could get a little better mileage- at least potentially- if you could stay out of the secondaries. But that's a tall order, the secondaries start to come in before the primaries are fully open.

Bottom line is what you have now, provided it's working right and tuned to the engine, is about as good as it gets unless you were to go to EFI. The engine tune and general vehicle condition will also effect mileage, but the biggest factor is still your right foot.

If you set up the Eddy carb, it will get some better than the stock 2g does. Best carb is a Quadrajet that is set up for your car.
NO other carb will get better than a Q Jet set up right and driven properly.
Get a vacuum guage and learn to drive by that. You will be amazed.

X2 on the Q-jet. I proved it to my self a few times in days gone by. A friend once bought my used 2bbl set up in hopes of improving economy. He found that his mileage was better with the 4bbl that he took off.

Hi,i had a 64 olds,with a 394 engine and 2 brl,got 5 mpg,swapped it for a manifold and 2 -500 carbs,milage went to 12 mpg...

Bob, two four barrel carbs out did a single 2 bbl for mileage...you're kidding, right?

__________________
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Midnight Sun Street Rod Association

That's not just because it was a 2-bbl carb. It had to have other problems. Unless you drove it WOT all the time. I got better than that (about 8 mpg) w/a Potiac 428 w/Tripower- and it was driven hard.

NO,thats not kidding,i thought i had a hole in my gas tank,that 2 brl carb,DRANK gas,the 2-4 brls outdid that 2 brl by 7 MPG. i know its hard to believe,but its the truth... that was on a trip from San francisco to Fort Lauderdale in 1964,car was NEW,drove across the states at about 85 mph...and NO AC...