Ford 5.0 Efficiency Build Advice

[Malykaii]

I already have an efficient 2.2 Camry. Now looking to build a luxury full size for fun, but am worried about mpg.

One idea is an 80's Town Car. Swapping to a stick shift out of a Mustang should up it by 2-3mpg easily.

Car starts at 15/20mpg and online forms report that being optimistic. Any advice on a realistic build that could see 19/25mpg? Thanks!

(Also another option that I like less is a Buick 3.8 swap into a 83-88 Seville that should realistically get 18/28mpg)

[Malykaii]

Only found one useful article so far for 5.0 mpg.

Basically says to de-stroke motor to 4.6, lower duration cam, and roller rocker arms.

Doesn't state any mileage results though

[Baltothewolf]

I got 25 out of my 302 stroked to a 331 with a 4.10 rear end. I had the auto though. And a really really good economy tune.

[Malykaii]

May I ask who did the tune?

Also, was the engine in a Mustang or a Full-Size/SUV?

Thanks!

[me and my metro]

My 91 Towncar got 21 highway consistsntly with 3.08 gears. They have a 2.75 set available. It was the first year for the 4.6 and the last year for the old aod. The 92 has a aode trans. We have some friends with a 94 with the 2.75 gears and they get about 24 on the highway.

[Baltothewolf]

I forget the name of the shop, they are in orange county CA. It was in a '91 Mustang with edelbrok rpm performer heads/intake, Anderson B31 blower cam, 1.6RR, a Powerdyne BD11A supercharger, aluminum driveshaft, built AOD and 4.10 rear end. Did 65mph on the freeway everywhere.

Just remembered after typing all that, I gained 2mpg by going to electric fan from mechanical fan. Also, advance the timing to 14° (from 10°).

[Hersbird]

I personally would start with a 2000's crown vic instead. They are really cheap at the police auctions and probably would get you those MPG's stock.
There is stuff like this every day
https://www.publicsurplus.com/sms/au...3D&auc=1950669

I actually see now the police version is rated quite a bit lower than the civilian. I would assume that is because it has much lower final gearing which would be an easy switch. The civilian crown vic was originally rated 17/25mpg in 2006. Uncorrected raw highway it laid down 31.7 mpg. The police version only 22.2 mpg so gearing makes a huge difference. P71 in the middle of the vin shows it's the police version.

I also was just looking at the Michigan police vehicle testing for 2006. The crown vic is an aero brick compared to the other cars there. The v-6 Impala that year with less horsepower went 142 MPH compared to 130 for the best unlimited Crown Vic. The v-6 Charger and Magnum (which make about the same hp as the v8 ford) went a little better 135 and 132 respectively. The Hemi Charger with a bunch more power went 150mph. That Impala is obviously the aero champ, but it is smaller as well. In 2012 when that older Impala got the new 300hp 3.6 it went 150 mph and got a mpg boost as well. (2 mph faster than a 365hp ecoboost Taurus that year.)

[Baltothewolf]

Hersbird. The police version of the crown Vic has a more aggressive ecu in it as well as the shorter gearing in the rear.

[Hersbird]

Originally Posted by Baltothewolf

Hersbird. The police version of the crown Vic has a more aggressive ecu in it as well as the shorter gearing in the rear.

And a cold air intake from the factory, shows how dumb those are.

[Stubby79]

a 3.8l Supercharged engine would probably give you decent economy...perhaps a mild supercharger on your 5.0 would boost it's efficiency also?