I just read a BUNCH of archive posts and feel I have a much better understanding of the whole Mech./Vac. secondary issue. But, I have one question: Would it be possible, with careful street driving (3.31 gears and 4sp.), to get better fuel efficiency with a DP carb?
Thanks in advance,
John

If you're "driving" for mileage, it doesn't matter how the secondaries are opened, cause if you're driving for mileage, they'll stay shut.

It's "possible" to get 18mpg outa my truck, around town, but it ain't much fun.

I agree with JimM. It sounds like your running a Holley DP; if that's the case, you might want to consider installing a 2 stage power valve in the primaries for better MPG. smile.gif

Better mileage with a DP than with a vacuum secondary carb...I doubt it. On second thought, just disconnect the linkeage to the secondaries and you're all set :D

That's what I was going to mention...

Max. mileage is created by driving like you have a "raw egg" under your gas pedal foot and only driving like 58/to 62 mph instead of say, 75/77 mph. And keep your tires pumped up to their max. rating to assure min. rolling resistance.

I can change my mileage from around 32 to upwards to 39mpg by just doing this commuting in my 2003 Hyundai Accent so know this stuff works... JUST drive like an OLD MAN!!!!

I love having a "corn-popper" car that gets good enough gas mileage that I can drive to down south of Birmingham to visit my Buddy and his wife without breaking the bank. But I miss that raw power a big V-8 makes!!!

pdq67

If you are after mileage use a Q-Jet and keep your foot out the back two ;)