Ford 390 "Efficiency"

[Eagle Kammback]

Not mine, but my friend is looking at a nice 67 Thunderbird, it's solid, and is an AMAZING price, has a 390. carb leaks like krazy, looking into something efficient, we know it's not fast, just want better than 10MPGs on the highway.
We'll probably put some headers and a decent exhaust system in it.
Yeah, researching a car before you buy it, but nonetheless, any ideas on how to make the car more "practical"
I was thinking an Edelbrock 650, but I only know motorcraft carbs, the one in it is an old Holley 4bbl

[TheSilverBuick]

Mine gets a consistent 17mpg highway on premium fuel. It will require premium unless the engine has been replaced or rebuilt with a lower compression one.

[squirrel]

I'd take a closer look at the Holley that's on it, might just need an overhaul. They do tend to leak when the gaskets get to be 10 years old.

There could be lots of things wrong with the car that we can't see from here....

[Huskinhano]

Try to find an old Autolite 4100 with 1.12" venturi. This is a really good carb that came on these motors. They use annular boosters that atomize the fuel better then the down leg boosters in the Holley. Very smooth running carb. I had a friend in HS who got a 66 Tbird with a 390 really cheap, like $150 cheap (hey, this was the early 70's). I seem to remember his saying he got really, really good gas mileage on the hiway. I want to say like 20 MPG but close to 40 years can embellish things. I just remember how shocked he was at how good it was on the hiway.

He tried everything to blow the C6 like doing neutral drops or flooring it the shifting into reverse after he got to about 25 MPH. The only thing that took a beating were the tires. It allway ran like a clock and never missed a beat.


Oh yeah, look into a good electronic distributor with vacuum advance.

[Barry Donovan]

I think of that too, the old cars and fuel efficiency.

my next one will mimick the fuel system of an 87 subaru, non-ecm carb.

40 below is nothing.

1967 has a full vent cap, no returns, a pulsing rubber diaghramed weirdo for a fuel pump.

that holley or oe carter, whatever.. they don't need to be strained, they don't need to leak. It is actually a sign of a well advanced cam on the intake side if a carb is straining.. (this means power), but they really do not have to. 1967 did that to snap the minds of egr cam inventors into torturing the world.

you could even have a solenoid to shutoff fuel bowl vent and idle jet (I have both on a 1987 subaru)

it may be the greatest carb setup I have ever learned.

count on 20+ from a oem high comp 390. high comp and fuel should equal sipping it down.. quite the opposite of rockheads that never evolved with the times.

I look forward to a project to mention here...alot of things I got planned learning from everytihng and anything I put my hands on.

[TheSilverBuick]

I wanted a 4100. I got the crappy 4300. I had to convert to pertronix on this car because it just wouldn't hold the dwell. My Centurion and old Firebird's never wandered.

[milner351]

FE parts aren't cheap, or plentiful, but they're out there and lots of guys are still running these engines every day in all sorts of applications.

Thunderbird FE headers won't be cheap new - look for a used set - but they wouldn't be my first part to replace.

Do a thorough tune up - rebuild the existing carb ($45 or so for a holley rebuild kit) and check out all the other stuff that can kill mileage - bad tires or low tire pressure, dragging brake, bad front end alignment...

[TC]

FE parts aren't cheap, or plentiful, but they're out there and lots of guys are still running these engines every day in all sorts of applications.

They are when you have a friend that is a Ford nut and owns a wrecking yard............At one time he had over 150 '65-'69 Mustangs..........

[milner351]

Thanks for telling me that now that I'm almost done gathering parts for the 69 mach1 power train....

[Barry_R]

Milner hads the quick answer - first fix what you've got before you start changing it around. Headers will help 'cuz the stock log manifolds ar pretty awful - but T-Bird headers are gonna be somewhere in between non-existant and insane. A 4500 pound car is never going to be a mileage package but it should not be that terrible if you work on the fuel curve and the timing.

I have no idea what the boxer3main guy is talking about. I would not be expecting 20+ from this deal no matter what you do. Unless it goes overdrive and EFI. Even then it would not be a lock. Pulsing diaphragm pumps worked pretty well for seventy or eighty years and are still fine for a fuel system that counts on an onboard, centrally located small reservoir of fuel and a needle/seat for proper metering.

[gearhed1971]

An interesting article on propane as fuel in an FE powered truck- http://www.ford-trucks.com/forums/58...fueled-fe.html