MPG?

[Tim Keith]

Keeping a fuel mileage log was a good way to know when the car needed a tuneup. In the days of points ignition that was being smart. Hardly anyone notices details like this anymore.

[Barabbas]

I agree Tim--I don't worry about the cost/mile of gas but MPG is a good measure of performance

[JBNeal]

As I prepare to do frame-off of my Pilot-House fleet, research has pointed me to conclude that the 8:1 CR + PCV + 180 t-stat + longer duration cam + increased induction + increased exhaust is the approach to wringing out as much energy as possible from a gallon of gasoline on these flatheads. Use of OD + <4:1 rear GR goes to maximizing torque output at modern highway speeds, further increasing mpgs.

The problem with 70s-era smog equipment was that it was a band-aid approach to cleaning air, as the engines at the time needed complete redesign of their combustion chambers & manifolds to maximize energy extraction from gasoline while minimizing hydrocarbon emissions. The smog pump robbed energy from the motor, reducing mpgs, just to push air into the exhaust stream to effectively meet gov't regulations.

When smog pumps finally started to disappear by the 90s, it was because engines had been re-designed to have cleaner emissions, with the byproduct of increased mpgs. Of note is the fuel-injected V6s offered by GM, Ford & Chrysler now that offer almost 300hp and produce a fraction of the hydrocarbon emissions of the 200hp V8s of the late 70s. More precise fuel delivery controls with freely flowing combustion chambers & manifolds make for high energy extraction from gasoline. Yep, this technology is more expensive than a 2bbl carb set with a screwdriver and a good ear, but the end result is supposed to be cleaner air.

Edited December 26, 2010 by JBNeal
additional engine mod info

[greg g]

Don't forget to advance the timing a bit to take advantage of the tighter squeezed fuel.

with higher compression, my 230 with two carbs, get 2+ better mpg than the single carbed 218 withthe same single exhaust. I run about 5 to 6 degrees of initial advance at idle.

I believe that works out to a 12% improvment or about 34 miles per tank. this with a 4.1 to 1 rear gear.

Wonder what a simple throttle body injector/s set up would do?

[Young Ed]

All I know is 1/4 on Annie means empty.

Go ahead...ask me how I found THAT one out!

Barabbas, thats a neat little piece of documentation there. I have similar for Annie that was written by the original owner.

My pickup is about the same. I blame it on the big dent in the bottom of the tank

[Barabbas]

All I know is 1/4 on Annie means empty.

Go ahead...ask me how I found THAT one out!

Barabbas, thats a neat little piece of documentation there. I have similar for Annie that was written by the original owner.

Kyle,

I was surprised at how well the notebook was preserved---it made me wonder about the previous owner, kind of like a Carcheology find.

BTW when Doris says "E" she only takes 5 gallons of gas. I'm assuming that she still has 5 gals in the tank--I'm sure that assumption will get me in trouble on some lonely highway

Mike

[JIPJOBXX]

Yea and the cow jumped over the moon!!!!!!!!!!!!!!!!