meteor, that's an interesting consideration.  I hadn't really thought about it but would have assumed that as long as the converter was filled and the clutches/bands fully applied, converter slip would be the same regardless of throttle pressure because the converter elements would not "care" what the pressure in the shell was relative to atmosphere.  I understand throttle pressure as balancing with governor pressure and influencing shift events (timing, quality, rate) and not having a significant direct bearing on converter behavior (beyond the effects of being in different gears). 

I'm working on my first measured tank of gas still, gauge is showing 5/8 full and I've gone about 100 miles.  That looks better than it's ever been but I also recalibrated the fuel gauge (so it wouldn't tell me I had fuel when I actually was empty).  Consequently, I don't know how I'm doing relative to the norm and will just have to wait and see until it's time to fill up.


1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

ted is bang on re the torque slippage,but torque charging pressure has a direct bearing on the slippage,which will never be eliminated toatley.shift quality and torque eficency are all controlled by pressure, via the control valve and the throttle pressure .adjustment. until these pressure are correct and to speck your search for better milage is like the dog chasing his tail.

While that statement is true for a standard transmission equipped vehicle, it does not hold true for an automatic transmission.  The torque converter by design does exhibit a given amount of slippage and where the rolling resistance is increased, the engine rpms will be higher versus where the rolling resistance is less.  The exception to this is the ‘lockup converter’ design which gets around the built in slippage factor but that lockup only occurs when the engine is under its least amount of strain.  Even within the manufacture of torque converters for the same application, there is a given amount of variability in the slippage between these.  This among other factors helps to explain why some cars although identical in manufacture have better fuel mileage than others.
 
The speedometer gear runs off of the transmission output shaft which will not reflect rpm variances from the converter forward.

Lorena, Texas (South of Waco)

DIrt could have put a strain on the fuel system and could cause bad mileage. Time for another road trip.

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

I was driving along and the fuel tank was low but I thought I had enough to get to a gas station.  Car quit and I figured it was lower than expected so I added the gallon of gas I carry around "just in case" which has been enough to get it to a gas station in the past but this time I got about 200 ft.  Got another gallon and another 200 ft, uphill.  Repositioned so car was pointing downhill and got it running, made it to a gas station, put 3/4 tank in, thought I was good, got about a mile before more of the same.

First thing I did when I got it back home was change the fuel filter, which seemed to fix it but got me about 5-10 miles before it started to act up again, but not as badly.  Took fuel pump apart, took carb apart, found a little sediment in carb bowls but pump was clean.  Put it back together and no trouble since then.  I'm not sure whether there was a problem with the fuel pump check valves or maybe it was sucking a bit of air at the hose junction to the fuel hardline.  

Just to be clear, it was not an ignition problem.  I disconnected the fuel line at the carb and verified that it was pumping intermittently.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

What were the fuel delivery problems you dealt with?

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

You're right, I still have not checked the trans throttle pressure.  I got sidelined on this issue by some fuel delivery problems that made the car unreliable for a few days, but it's back in action now.  The trans throttle pressure & stall check are next on the list of things to look into.

Meanwhile, I can report that something (I wish I knew what) has definitely changed.  Throttle response has always been very linear and a bit soggy--I remembered my 292 '59 Galaxie feeling more punchy than this 312 car and figured it was a consequence of the CI FOM as opposed to the later aluminum one the Galaxie had.  Well, now, the 312 is awake!  If I am very gentle with the throttle, the first little bit of pedal travel gives light acceleration, but if I push it just a little farther (we're talking 1/4 throttle at most, by the feel), there is a surge of power stronger than what I have grown accustomed to with this car.  The long shot of it is that I don't have to give it as much throttle as I used to to get the same rate of acceleration.  I don't believe this to be caused by removing rolling resistance, though I can't say for sure.  It just seems that when the throttle plates open enough to pull in the main fuel circuit, it does so with new strength.  No carb settings have changed and I have been through this carb checking for blocked passages and the like many times with no trouble indicated.  This is a new development so I haven't been able to tell whether it has helped or hurt economy.  I will be driving the car a lot now so I'll post back when I know.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

seems you have not checked a verry critical part of the power train. trans throttle pressure adjustement. Torque stall,must have a acurate tack. if torque stall is high,check trans presures,and torque charging presure. a poorly set up trans will acount for 5 or so mpg. torqe stall will tell you the health of the engine as well

I was watching the Andy Griffith show when aunt Bea's sister and family came to visit in a 55 Ford and her husband was saying he got 15 miles to the gallon on the trip so I do not think they are gas misers.


Butchering up everything I can get my hands on in Dayton Ohio

I worked in a brake shop for a few years and the raised spots on the backing plates must be smooth. We would flat file them as necessary. No high spots. We always replaced the springs no matter what and always put lubriplate on every raised place where the shoes rode. I could tell when doing a brake job if the last shop knew what they were doing by the chamfering of the shoes and the evidence of lubriplate on the backing plates and the adjusting screw... Good luck.

56 Vic, B'Ville 200 MPH Club Member, So Cal.