I've looked at the gear vendor setup but I would have to cancel work on my roadster to buy one! I'd love to get 21mpg but will have to get through the learning curve on the 4-71 blower and 325 cubes. Chuck

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'm guessing you won't be too concerned with mileage with that new setup.

I am confident that I have a 3.10:1 gear.  I got my revs/mile for each tire from this page: http://www.carnut.com/specs/tires.html  It gives a 7.50x14 tire at 750 revs/mile.  That comes out to 2325 rpms at 60 and 2712.5 at 70; it will be more with the radials I mentioned because they are 764 revs/mile.  That 2712.5 at 70 assumes no slip whatsoever.  It's what a manual transmission or lockup converter would give.  I have an open torque converter so I expect higher revs than that.  

My converter is showing a 10% rpm gain relative to that "lockup ideal."  According to my internet snooping, most converters give 3-5%--but it is referring to modern converters, not 50-year-old designs.  Can anyone here with a stock Fordomatic verify less than 10% slip?

Also, I can post in detail my current advance characteristics if anyone thinks that would help clear up the picture.

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

I'm all out of ideas

what is the torqe stall # ,if it is higher than spec,you may have to increase torque charging pressure,if low torque pressure it will increase the slippage.all torque
converters have some slippage,high stall tells you ther is low charge or internal issues  with converter.still think your ratio in diff is to low for decent fuel economy. if memory is correct the torqe pressure can be increased with new spring ,located along side of trans pressure spring. throtel pressure seting is also critical as well. if you can find a older motors repair manual ther is good info on tp adjustemnt as well the rest of transand valve bodey

My last shot in the dark. The plugs look rich to me, and Charlie's post would indicate that. Do you have the right springs on the step up rods, or would a change help. It's been too long since I tuned an AFB, but IIRC, the rods determine the enrichment, and the springs the vacuum level they come in at. If you're running on the "rich" circuit at cruise that would do it.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

My milage is crap. Stock 292, fordomatic, 3.21 gears, 57 dist, and of course dual quads. The best it ever did with a single WCFB was 12 mpg all in town driving. Tail pipes were spotless; now with dual quads it's 10/11 with the same in town driving ( I drive like a grandma and a max of 65 on the Ca. Freeways ) tail pipes are still spotless. Mostly I blame the automatic as our 56 in 56 didn't do much better new. To me the best improvement would be a fuel injection unit like the one MSD makes. It a long with one of their dist. and a cut up stock air cleaner to hide it all would be pretty cool, but not as cool as the 2 quads. A better automatic would help too.... Good Luck

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

How about tuning with an Air/Fuel meter?
That's how I did my 32 and it made a huge
difference in both performance & mileage.
Then, a Ford AOD
There, I'm almost done.
Except 1) I don't believe there is a 10% slippage in the torque convertor
Except 2) to say that the dual quads are the COOLEST

My tires are 28" IIRC.  With 3.73 gears in 4th (I have a T5 but 4th is 1:1) at 70 MPH the tach shows 3000 RPM.  Sounds like your rear end ratio calculation is off.
TC

You gotta have the right tools and know how to use 'em.

TC - Austin, Texas

I'm not sure whether 10% is normal for the Fordomatic converter or not, but I do recall my '59 Galaxie with a 3.10 gear being within 100 rpm of the numbers I am seeing with my Fairlane.  The Galaxie had the 2-speed aluminum case Fordo.  

Miker, if you think my plugs look rich, I'm thinking I will not invest any more time or energy on the AFB and finish putting together my Autolite 4100 instead.  I haven't heard of anybody else running that early AFB, perhaps it was extra inefficient.  I know the high-speed air bleeds tend to get a film across them which could contribute to rich running.  I had a 2100 on my '59 and was very pleased with it.

I'm going to replace the read brake shoes as well.  The linings are very old and they look fine but sometimes I suspect they are hanging on a little bit after they are applied.  For example, when I release the parking brake after the car has been parked for a while, it does not start rolling when I drop it into reverse without a little throttle.

I am guessing (hoping?) that this poor economy is the sum of several minor contributors adding up to a noticeable impact.

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