24mpg average on the Hwy, 17mpg City w/ the 223 I-6, Mer-O-Matic, 15x7.00, 3.70 in the Pumpkin'.
Will find out hopefully by the end of the month what my 312 I-6 w/ the HD C-4, 15x7.00, 3.23 & Tru-Trak in the Pumpkin' well be getting.

 

guys, I dont know what I get(odeometer inop) but it aint good!!!!!!! I have a223 with a 4spd.

 

the 60 has a 223 six, 3:89 rear gears and overdrive trans, gets 18-19 on hiway, my 66 f250 with 352, 410 gears gets 10mpg if its downhill with a tail wind

 

I know...really old thread. Anyone checked theirs recently? I am trying to get a better guesstimate for the gas cost of a possible supernats trip.

Mine is a stock '56 272 Y-block (?), 3 speed, and supposed to be 3.73 gears.

When the weather warms up a little, I need to do some shorter runs and check it. A 1300 mile round trip at 10 mpg would not good at all.

 

I have a 223 in my 57 . It had a 3:70 in it, mileage was about 10. I have since replaced my 3:70 with a 3;25 and since I have a 4spd it does a lot better. Also repaired my odmeter, so I can say that I now get 14-15 now. Not great, but much more fun to drive on the big road. Wish now that I would have installed a 3:00. Could have used granny as my takeoff gear, and that baby would have really been turning slowly on the interstate. By the way I still have that 3:70 and its in terrific condition.

 

Roy

That's the Worst MPG I've Ever heard a stock 223c.i.er get, something else has to be wrong or out of wack.

 

What should I get ??? Roy

 

I paid $3.29 a gallon in Needles, Ca the first of this month - so mileage on trips is important. I get 15 out of my jeep pulling my featherweight camp trailer, if I can't get 18 out of my 59 I will be disappointed.

 

My 351 in my 58 gets 30 or 40 gallons a year.Sure be glad when its ready to put on the road.Gas milage wont be good,but who cares as long as Its on the road.

 

I get 9-10 mpg out of my C600 unloaded with 6.50/8.77 gears, 10.00-20.0 tires, 5 speed manual, 14' flatbed, and a 292 with one wiped intake lobe. Gotta fix that.

 

I averaged 25mpg Hwy w/ mine & 17-20mpg City, w/ a Merc-o-Matic, 3.70 Rear Gear, 7.10x15 tires Bone Stock 223c.i.er w/ 95,000+ miles on the "Olde Girl".

 

i have a 1948 ford f1 with a 49 mercury flathead v8 and org 4speed i get 20 to 23 mpg with dual exht and fresh rebuild

 

my 69 only got 12-14 if i was lucky, closer to 13-15 now that i put one of them tornados on, however the 53 should do 20 because of the 5.0 efi/aod that is in it now.... that along with the 2.71 rear end should pop it up really high...the car alll that stuff came out of never made less than 25...heres hopin

 

The Jet Mobile is currently doing 18 on the highway. I am disappointed with the number but we are changing the rear. The only thing that was not changed was the rear. I had a 302 and a C-4. Never thought about the rear ratio. After the new 302/320hp and the AOD I realized the ratio was a 2.21 or 2.23 whatever the GM ratio was, the tires are 225-75-15. Normal driving takes 53 mph to change to 3rd gear. At 75 mph the rpm is 1480 in OD. If I lived in flat land this might work, but here in the hills it changes all the time. For it to change to OD you have to get to 78 mph and then you can slow down to 73-75. If you drop to 70 it will downshift. The new,revised new plan is a 3.08 or a 3.23 ratio. I believe this will increase mileage as it won't be in 2nd around the city and for highway driving I won't be pressing as hard to run 75mph, that is the highway target speed. The Jet Mobile is a daily driver and has 3500 miles since January 1st, which is about normal for me, about 18 to 20k miles per year.

One thing I have learned is that once you build it the way you want, you will change all the things you have found that you don't like.

 

Very interesting. I am going to run a Mustang H.O. 302 with an AOD. I don't know what rear end gear I have yet. My current Mustang 5.0 ran 2 mpg better AFTER I swapped the 2.73 gears for 4.10's......go figure.