Been building a 210, two door, A14 engine, 5 speed for several years, slowly gathering parts. Converted the car from a 4 speed to 5 speed. Added a round port high compression cylinder head, decked the block and milled the head for 10:1 compression ratio. Also added a new in box mpg Hitachi carburetor, but have not adjusted the air fuel ratio. Kept the A14 dual pattern camshaft.
Finally have the car running. Have 300 miles on the car so ran a fuel economy run, but only got 44 mile per gallon.
Specs of the run are:
126 mile round trip.
air temp 23 degrees F (-5 celcius).
max elevation change: 1560 feet.
wind was 20-29 mph from various directions.
rear axle ratio: stock 3.7:1, could not find used pumkin with 3.5 mpg ratio.
Tire size 175/70 R13, about 22 inches diameter.

I'll tune some more and wait for warmer weather and not so much wind, then try again.

Question: did the mpg engines have a dual or single pattern camshaft?
I meant to put this post in the B210 section.

Nice work. But why not take 15 minutes to adjust the idle mixuture?

1979 engines, MPG or not, used the same A14 camshaft.

Aussie gallon is about 4.5L. US is 3.8 ??? What rpm were you sitting on with 5sp + 3.7 ratio on 60 miles /100klm ??

Given the cars aerodynamics if you got 44 mpg on a windy day that's pretty good.

Some other thoughts; make sure the choke is all the way open, what tires pressures and what alignment settings?

Tom

you changed elevation 1600 feet in 129 miles and still got 44mpg with an undajusted carburetor. You just killed a Prius, you should pat yourself on the back!!!

What part of MT are you in, once lived there before.

Thanks for all the encouragement. I did not mean to be confusing...I had set the carb idle air/fuel ratio, but have not checked the cruise A/F ratio. The choke was open for sure, I cheated on the tire pressure with 46/42 psi front/rear. Tires had not been aligned yet, they were toed out a little, but another snow storm was coming and I wanted to get the run in before the roads turned icy. At 60 mph the engine was turning at 2780 rpm according to internet calculators (22 inch diam tire, 3.7 axle ratio, 5th gear ratio is 0.82).
I'm in Bozeman, drove over Bozeman Pass to Big Timber and back using the highway markers to verify distances.
Ignition timing set at 10 degrees advanced with factory electronic ignition advance curve.

I noticed the mpg carburetor has a smaller primary throttle bore than "normal" A14 carb. My other Datsun, a 1976 B210 Coupe with A12 engine and 3.89 axle gears has a little quicker acceleration and higher cruise speed (85 vs 75 mph)at maximum throttle opening on the primary bore only. The A12 has 10:1 compression also.
I was a factory trained Datsun mechanic back in the late 70's, its fun messing around with the Datsuns again..they are a great little car:)