Fuel Efficient 383

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Dave's Big Block Mopar Garage General 1958-1978 Dodge - Coronet

Fuel Efficient 383

My coronet has a 383 in it it gets about 12 mpg. Without using fuel injection what do you think is the best way to make it somewhat fuel efficient.


If only there were a magic bullet…

The single easiest and most effective fuel economy improvement comes from changing your driving style. Ease up to traffic light, accelerate very moderately, maintain steady speeds not over 60 MPH….etc. etc. City or suburban, this can be worth 50-75% improvement! But that’s what Prius’ are for, nobody wants to drive their classic mopar like a tree-hugger. Fork that!

So here’s a short list, remembering the first sentence…these are approx. order of effectiveness:

> Tallest axle ratio you can find (typically, that means 2.76:1). This actually makes the car much more pleasant on the highway. Or OD tranny.

> If A.T., a tight torque converter, lockup even better

> Plenty of vacuum advance – total timing in the area of 55 deg. BTDC at cruise

> Light synthetic engine oil (10W30)

> Inflate tires to 35-40 PSI

> Low restriction exhaust – headers, etc.

> Camshaft with minimum overlap, and highest C.R.

After this, the improvements get smaller and harder to come by, some example: remove right side mirror, lower front of car, smallest fan, loosen wheel bearing adjustment, higher temp thermostat, etc.

It is possible to get close to 20 MPG from a 383 in “flatland”. But, again, read the first sentence!


over 4 years ago

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