What kind of mileage can you expect from a well tuned 1.7 with dual 40 carbs?

I would say 30mpg

29ish on the highway. Way less zipping around town in 2nd and 3rd gear.

It was set up with a single carb that sucked and it did not do well on gas mileage at all. I am going on a 900 mile round trip starting tomorrow and we'll see how it does now.

My 914(1.7 stock f.I) used a full tank for my weekly commute

My Mazda protege also used a full tank

16 gallons vs 12.5

And the Mazda gets about 28 mpg

So the 914 get less I'm guessing 25 mpg which is damn good I think

would the FI engine get better gas mileage?

FWIW, my nicely tuned (thank you again Heeltoe914) 2.0l with twin Weber 40s gets about 23 mpg in mixed use driving. I'd think you'd get around 28 mpg with a carbureted 1.7 in highway use at reasonable speeds.

With a single Weber kit, expect 15-ish

My 2.0 with 40 webers and hot cam got 28 highway, my stock 1.7 with fi gets 36.

Mark, that's sick mileage on your 1.7. I assume that's primarily highway driving, right? What do people typically get on "parkway" driving like I do going to and from work? I think I'm sub-20 MPG which pales compared to what some report. The parkway driving is 50 mph for a mile and a half then stop at a light. Rinse, repeat, etc.

Fifteen mpg on a1.7 with a single Weber? I'm not buying it. You had another problem. I got almost 40 mpg from my injected 1.7, and over 30 on a 2.0 with a single Weber. I now have that same 2.0 which is now a 2056 with Raby cam, and the fuel injection reinstalled that still gets over 30 on the hiway. If your getting crap mileage from a 914 make sure that all the settings (dwell, timing, valves, etc) are correct and you have adequate compression before blaming the induction system.

Around town I'm seeing upper 20's -30 from the 1.7. I never saw less than 20+ from my 2.0 no matter how I drove it.
The guys who drive stock 3.2 - 911's report low to mid 20's on the highway so I'm expecting at least that much from my 3.2 GT build.

The fuel injected 914s I had in the 70s got good local mileage, and I remember leaving NYC around 4:30am and crossing the Pennsylvania border into Ohio before filling up. I don't remember where we filled the tank the second time, but we pulled into Cedar Rapids, Iowa that night with some fuel in the tank.

Just about 1,000 miles. 35mpg sticks in my mind.

15gallons x 35 mpg = yeah, we did 400 miles between stops.

Speed limits west of Pennsylvania were 75 and the car was comfortable at that speed.

Gas was about $.35 a gallon, so I never paid too much attention to mileage....

Wow. I need to look at this closer to see what I'm really getting. Or brush up on my basic math and division skills....

Thanks all I drove it on the same trip last year with a single carb and I thought I was going to go broke buying gas.

Something's wrong. A single carb is not optimal but should still work ok. At least get you from a-b without sucking up too much gas.
I filled up before Hershey -70 miles and then filled up again before the rally. I could only get 2 gallons in the tank. I know that's not scientific and maybe I really used 2.5 but the point is these cars sip gas, not gulp it. If milage sucks, there's something wrong.

Like your's Curt, Ljet on a 2056 with a 9550 cam, 9:1 comp. I only get about 24 mpg on the highway, but I believe it's mostly due to not keeping my foot out of it. One of these days I'll try not doing so, and see if that helps.

It's just too damn fun...

all of my carb'd cars got around 23 mixed.
altitude and slightly richer mixture on purpose for heat reasons/DE driving.

a 1.7 should beat that

I could beat 30mpg highway if I found a way to cheat
(once drafted a semi above the speedlimit at night for 100miles... about 33 that night)

my fi 1.7 did much better... over 30 regularly on the highway at altitude

in the 2.0FI with a slightly tweaked mps (jason's motor) I just drove to newport beach in the spring... lots of highway miles, but some days of twistys around palm springs, skirting joshua tree, and stop and go traffic for hours on the coast........ 2500+ miles in about 5 days...
29.something mpg average

I do lots of I5 cruising, 550 miles at a stretch. In 5th gear at 3000 rpm is a bit north of 70mph gets me 29-30mpg. If I'm down to 65mph (2850rpm?) I'm into the low 30's. Over 80 mpg average and I'm 27-28mpg. All of that is over 400 miles a tank.

Dual carbs, no FI.

Enjoy your trip!